Verb Scale IV: taktēb

Αμμίθκαλ Αδρωβιτεί: τακτήβ

8.1 Introduction to taktēb Verbs

Taktēb (Scale IV) is the reciprocal stem, whose primary purpose is to make transitive stems intransitive by adding an implication of reciprocity: τακτήβ taktēb “write one another, exchange letters, correspond” (from *ktāb “write”). A great many verbs denoting social interaction are found in this scale due to its reciprocal nature and, in this sense at least, Scale IV verbs are very rarely seen with singular subject agreement. Stative roots may also appear in taktēb, where they indicate transformation: ταλβήν talbēn “become/turn white” (*lbīn “white”), τασδήρ tasdēr “get ready” (*sdīr “ready”).

Its most distinctive feature is the prefixed *t- seen in all forms, although with some roots this *t- will instead be infixed after C1 in several forms. In Semitic studies this conjugation is known as the tB-Stem, since it was historically derived from the B-Stem (Scale I). Since it is exclusively intransitive, taktēb has no passive counterpart.

8.2 Triconsonantal Roots and taktēb

8.2.1 The Present Tense

The regular present tense is formed by adding prefixes and suffixes to the stem *-tC1aC2VC3-. The 'V' represents the inherent vowel of the root, and so can be either -ā-/-ī-/-ē- (in unsuffixed forms) or -a-/-i-/-e- (in suffixed forms). Outside of the first person singular, the prefix vowel is based on Barth's Law: /i/ if the stem vowel is *ā, or /a/ if the stem vowel is *ī or *ē.

Note that since reciprocal verbs generally can't have singular subjects, several of the forms of the verb τακτήβ taktēb “write each other” shown here and later on (as well as for some other verbs later in this chapter) are hypothetical and are included for demonstrative purposes. On the other hand, all of the forms of ταλβήν talbēn “turn white” are in use, since this verb is not reciprocal in meaning.

8.2.2 The Preterite Tense

The preterite is formed by adding the regular preterite endings to the stem *taC1C2ēC3. They are thus identical in form to the 'aktēb preterite, but with the prefix *ta- rather than *'a-.

Scale IV Preterite Tense: taktēb “write each other”
Person Singular Plural
1st τακτήβετ
taktēbet
τακτηβνώ
taktēbnā
2nd Masc τακτήв̄τα
taktēvta
τακτήв̄τυν
taktēvtun
2nd Fem τακτήв̄σ̄ε
taktēvše
τακτήв̄σ̄ιν
taktēvšin
3rd Masc τακτήβ
taktēb
τακτηβού
taktēbū
3rd Fem τακτηβώ
taktēbā
τακτηβού
taktēbū

8.2.3 The Imperfect Tense

The imperfect tense is formed by adding endings to the stem *taC1C2ieC3. They are thus identical in form to the 'aktēb imperfect, but with the prefix *ta- rather than *'a-.

Scale IV Imperfect Tense: taktēb “write each other”
Person Singular Plural
1st τακτιήв̄
taktiev
τακτιήв̄εν
taktieven
2nd Masc τακτιήв̄ετ
taktievet
τακτιήв̄τυν
taktievtun
2nd Fem τακτιήв̄ες̄
taktieveš
τακτιήв̄σ̄ιν
taktievšin
3rd Masc τακτιήβ
taktieb
τακτιηβού
taktiebū
3rd Fem τακτιηβώ
taktiebā
τακτιηβού
taktiebū

8.2.4 The Perfective Subjunctive Tense

The perfective subjunctive is formed by adding a special set of prefixes to the stem *-tC1aC2VC3, where 'V' is the short vowel of the inherent root vowel. These prefixes are *vā- (first person singular), *vəna- (first person plural), *vəta- (second person), and *vī- (third person).

8.2.5 The Imperative

The imperative is formed from the stem *tiC1C2VC3-/*taC1C2VC3-, where 'V' is the long version of the root vowel in the masculine singular and the short version elsewhere. Barth's Law applies to the vowel after the initial /t/ 1 .

8.2.6 Deverbatives

The infinitive is formed from the pattern *matC1aC2ēC3, and the participle from *mitC1aC2iC3.

Scale IV Deverbatives: taktēb “write each other”
Infinitive Active Part.
Form ματκατήβ
matkatēb
μίτκατιβ
mitkatib
Meaning write each other writing each other

8.3 Biconsonantal Roots and taktēb

Biconsonantal roots follow a very similar paradigm to triconsonantal roots. However, they retain their internal root vowel in all forms other than the imperfect, where it is replaced by *-ie- for all verbs.

The tables below show the complete conjugation of the verbs τατζείλ tačīl “become cold, get cold” (*čīl “cold”) and ταρ̄ούν tařūn “become hot, turn hot” (*řūn “hot”).

Scale IV Conjugation: tačīl “become cold”
Present Preterite Imperfect Pf. Subj.
1st Sg αττζείλ
'atčīl
τατζείλετ
tačīlet
τατζιήλ
tačiel
в̄ωττζείλ
vātčīl
2nd Sg Masc ταττζείλ
tatčīl
τατζείλτα
tačīlta
τατζιήλετ
tačielet
в̄αταττζείλ
vətatčīl
2nd Sg Fem ταττζειλεί
tatčīlī
τατζείλσ̄ε
tačīlše
τατζιήλες̄
tačieleš
в̄αταττζείλ
vətatčīl
3rd Sg Masc ιαττζείλ
yatčīl
τατζείλ
tačīl
τατζιήλ
tačiel
в̄ειττζείλ
vītčīl
3rd Sg Fem ιαττζειλεί
yatčīlī
τατζειλώ
tačīlā
τατζιηλώ
tačielā
в̄ειττζείλ
vītčīl
1st Pl ναττζειλού
natčīlū
τατζειλνώ
tačīlnā
τατζιήλεν
tačielen
в̄αναττζείλ
vənatčīl
2nd Pl Masc ταττζειλού
tatčīlū
τατζείλτυν
tačīltun
τατζιήλτυν
tačieltun
в̄αταττζείλ
vətatčīl
2nd Pl Fem ταττζειλού
tatčīlū
τατζείλσ̄ιν
tačīlšin
τατζιήλσ̄ιν
tačielšin
в̄αταττζείλ
vətatčīl
3rd Pl ιαττζειλού
yatčīlū
τατζειλού
tačīlū
τατζιηλού
tačielū
в̄ειττζείλ
vītčīl
Imperative Deverbatives
Masc Sg τατζείλ
tačīl
Infinitive ματτζείλ
matčīl
Fem Sg τατζειλεί
tačīlī
Participle μιττζείλ
mitčīl
Pl τατζειλού
tačīlū
Scale IV Conjugation: tařūn “become hot”
Present Preterite Imperfect Pf. Subj.
1st Sg ατρ̄ούν
'atřūn
ταρ̄ούνετ
tařūnet
ταρ̄ιήν
tařien
в̄ωτρ̄ούν
vātřūn
2nd Sg Masc τιτρ̄ούν
titřūn
ταρ̄ούντα
tařūnta
ταρ̄ιήνετ
tařienet
в̄ατατρ̄ούν
vətatřūn
2nd Sg Fem τιτρ̄ουνεί
titřūnī
ταρ̄ούνσ̄ε
tařūnše
ταρ̄ιήνες̄
tařieneš
в̄ατατρ̄ούν
vətatřūn
3rd Sg Masc ιτρ̄ούν
yitřūn
ταρ̄ούν
tařūn
ταρ̄ιήν
tařien
в̄ειτρ̄ούνλ
vītřūn
3rd Sg Fem ιτρ̄ουνεί
yitřūnī
ταρ̄ουνώ
tařūnā
ταρ̄ιηνώ
tařienā
в̄ειτρ̄ούν
vītřūn
1st Pl νιτρ̄ουνού
nitřūnū
ταρ̄ουννώ
tařūnnā
ταρ̄ιήνεν
tařienen
в̄ανατρ̄ούν
vənatřūn
2nd Pl Masc τιτρ̄ουνού
titřūnū
ταρ̄ούντυν
tařūntun
ταρ̄ιήντυν
tařientun
в̄ατατρ̄ούν
vətatřūn
2nd Pl Fem τιτρ̄ουνού
titřūnū
ταρ̄ούνσ̄ιν
tařūnšin
ταρ̄ιήνσ̄ιν
tařienšin
в̄ατατρ̄ούν
vətatřūn
3rd Pl ιτρ̄ουνού
yitřūnū
ταρ̄ουνού
tařūnū
ταρ̄ιηνού
tařienū
в̄ειτρ̄ούν
vītřūn
Imperative Deverbatives
Masc Sg τερ̄ούν
teřūn
Infinitive ματρ̄ούν
matřūn
Fem Sg τερ̄ουνεί
teřūnī
Participle μιτρ̄ούν
mitřūn
Pl τερ̄ουνού
teřūnū

(The prefix vowel *e in the imperative of tařūn is the result of the lowering of original *i due to the following *ř. This lowering does not take place in the present tense due to the intervening -t-.)

8.4 Quadriconsonantal Roots and taktēb

Quadriconsonantal roots cannot appear in Scale IV. Instead, they must use the morphology usually reserved for European loan verbs described in section 13.

8.5 Geminate Roots and taktēb

Geminate roots in taktēb are somewhat complicated, as they switch between triconsonantal- and biconsonantal-like paradigms without a clear pattern. For this reason each tense will be discussed separately. The verb ταμήλ tamēl “promise one another, be engaged” (*mall “promise”) will be used to demonstrate.

8.5.1 The Present Tense

In the present tense, geminate roots behave triconsonantally (with root vowel *ā) when no suffix is present and biconsonantally (with root vowel *a) when a suffix is present.

Scale IV Present Tense: tamēl “promise one another”
Person Singular Plural
1st ατμαλώλ
'atmalāl
νιτμαλλού
nitmallū
2nd Masc τιτμαλώλ
titmalāl
τιτμαλλού
titmallū
2nd Fem τιτμαλλεί
titmallī
τιτμαλλού
titmallū
3rd Masc ιτμαλώλ
yitmalāl
ιτμαλλού
yitmallū
3rd Fem ιτμαλλεί
yitmallī
ιτμαλλού
yitmallū

8.5.2 The Preterite Tense

In the preterite tense, geminate roots always behave biconsonantally, although they have the root vowel *ē like triconsonantal verbs. The gemination only surfaces when followed immediately by a vowel.

Scale IV Preterite Tense: tamēl “promise one another”
Person Singular Plural
1st ταμήλλετ
tamēllet
ταμηλνώ
tamēlnā
2nd Masc ταμήλτα
tamēlta
ταμήλτυν
tamēltun
2nd Fem ταμήλσ̄ε
tamēlše
ταμήλσ̄ιν
tamēlšin
3rd Masc ταμήλ
tamēl
ταμηλλού
tamēllū
3rd Fem ταμηλλώ
tamēllā
ταμηλλού
tamēllū

8.5.3 The Imperfect Tense

The imperfect tense also behaves biconsonantally, with the usual imperfect marker -ie- generalized as the stem vowel. Gemination only surfaces when followed by a vowel.

Scale IV Imperfect Tense: tamēl “promise one another”
Person Singular Plural
1st ταμιήλ
tamiel
ταμιήλεν
tamiellen
2nd Masc ταμιήλλετ
tamiellet
ταμιήλτυν
tamieltun
2nd Fem ταμιήλλες̄
tamielleš
ταμιήλσ̄ιν
tamielšin
3rd Masc ταμιήλ
tamiel
ταμιηλλού
tamiellū
3rd Fem ταμιηλλώ
tamiellā
ταμιηλλού
tamiellū

8.5.4 The Perfective Subjunctive Tense

All perfective subjunctive forms appear triconsonantal for geminate roots.

Scale IV Perfective Subjunctive: tamēl “promise one another”
Person Singular Plural
1st в̄άτμαλαλ
vātmalal
в̄ανάτμαλαλ
vənatmalal
2nd в̄ατάτμαλαλ
vətatmalal
в̄ατάτμαλαλ
vətatmalal
3rd в̄είτμαλαλ
vītmalal
в̄είτμαλαλ
vītmalal

8.5.5 The Imperative

The imperative is biconsonantal, with the root vowel *ā in the masculine singular and *a in the feminine singular and plural.

Scale IV Imperative: tamēl “promise one another”
Person Singular Plural
Masculine τιμώλ
timāl
τιμαλλού
timallū
Feminine τιμαλλεί
timallī
τιμαλλού
timallū

8.5.6 Deverbatives

Both the infinitive and participle behave triconsonantally.

Scale IV Deverbatives: tamēl “promise one another”
Infinitive Active Part.
Form ματμαλήλ
matmalēl
μίτμαλιλ
mitmalil
Meaning promise each other promising each other

8.6 Weak Roots in Scale IV

8.6.1 C1 = Ř

Root-initial *Ř is completely regular except in forms with prefix vowel /i/ (i.e., the present and imperative of roots with stem vowel *ā or *ū), where it is lowered to /e/. This was seen previously in the conjugation of ταρ̄ούν tařūn “become hot” (*řūn “hot”).

8.6.2 C2 = Ř

Medial *Ř does not trigger any irregularities. Verbs such as ταλρ̄ήβ talřēb “widen, become wide” (*lřāb “wide”) are regular.

8.6.3 C3 = Ř

Root-final *Ř affects the feminine suffix *-ī in the present tense and infinitive, which becomes *-ēyi. The verb τασλήρ̄ təslēř “get lucky” (*tshlār “successful”), for instance, has the form ιτσαλαρ̄ήι yitsalařēyi “she is having good luck” instead of regular **yitsalařī. In addition, the last vowel of the participle is lowered to /e/: μίτσαλερ̄ mitsaleř “lucky, being lucky” (not **mitsaliř).

8.6.4 C1 = '/H

Roots with initial *' and *H behave identically. The root *'mār “say” is one example, giving the Scale IV verb ταηαμήρ tahamēr “say in unison”.

When the prefixed *t of taktēb comes in direct contact with C1 (in the present, perfective subjunctive, and deverbatives), C1 drops, the prefixed *t becomes an aspirated *th, and any preceding short vowel is reduced to schwa: νατταμαρού nəthamarū “we are speaking in unison” (not **nit'amarū), в̄είτταμαρ vīthamar “[that] they spoke in unison” (not **vīt'amar).

If C1 does not come in direct contact with the prefixed *t, then it will always surface as /h/ together with an epenthetic /a/ to prevent illegal clusters: ταηαμήρτυν tahamērtun “you all (m) spoke in unison” (not **ta'mērtun), ταηατιηβού tahatiebū “they were speaking in unison” (not **ta'tiebū).

8.6.5 C2 = '/H

Roots with medial *' or *H (such as *k'ār “be ashamed”, giving τακκήρ təkhēr “become ashamed”) are regular in some forms, and show assimilation in some others.

When C2 is intervocal (in the present, perfective subjunctive, and deverbatives), the verb conjugates regularly: ατκαώρ 'atka'ār “I am becoming ashamed”, μίτκαιρ mitka'ir “becoming ashamed”.

When C2 is not intervocal and therefore in contact with C1, it assimilates into C1, resulting in gemination or aspiration. If aspiration appears, preceding short vowels will reduce to schwa: τακκήρσ̄ε təkhērše “you (f) became ashamed” (not **tak'ērše), τακκιήρ təkhier “he was becoming ashamed” (not **tak'ier).

8.6.6 C3 = '

As elsewhere, root-final *' behaves erratically. The root *brī' “clear” gives the Scale IV verb ταβρή tabrē “become clear, clear up”.

In the present tense, the glottal stop drops when word-final and is present elsewhere:

Scale IV Present Tense: tabrē “become clear”
Person Singular Plural
1st αδ̄βαρεί
'aḏbarī
ναδ̄βαριού
naḏbari'ū
2nd Masc ταδ̄βαρεί
taḏbarī
ταδ̄βαριού
taḏbari'ū
2nd Fem ταδ̄βαριεί
taḏbari'ī
ταδ̄βαριού
taḏbari'ū
3rd Masc ιαδ̄βαρεί
yaḏbarī
ιαδ̄βαριού
yaḏbari'ū
3rd Fem ιαδ̄βαριεί
yaḏbari'ī
ιαδ̄βαριού
yaḏbari'ū

The preterite features the special set of aspirated suffixes rather than the normal set. The glottal stop disappears in all forms other than the third person singular feminine and third person plural. Additional contraction takes place in the first person singular:

Scale IV Preterite Tense: tabrē “become clear”
Person Singular Plural
1st ταβρήτ
tabrēt
ταβρηννώ
tabrēnnā
2nd Masc ταβρήττα
tabrētha
ταβρήττυν
tabrēthun
2nd Fem ταβρήτζζε
tabrēčhe
ταβρήτζζιν
tabrēčhin
3rd Masc ταβρή
tabrē
ταβρηού
tabrē'ū
3rd Fem ταβρηώ
tabrē'ā
ταβρηού
tabrē'ū

In the imperfect the glottal stop also drops in all forms other than the third person singular feminine and third person plural. The sequence -ie'e- contracts to just -ie-. The second person plural forms continue to use an aspirated ending.

Scale IV Imperfect Tense: tabrē “become clear”
Person Singular Plural
1st ταβριή
tabrie
ταβριήν
tabrien
2nd Masc ταβριήτ
tabriet
ταβριήττυν
tabriethun
2nd Fem ταβριής̄
tabrieš
ταβριήτζζιν
tabriečhin
3rd Masc ταβριή
tabrie
ταβριηού
tabrie'ū
3rd Fem ταβριηώ
tabrie'ā
ταβριηού
tabrie'ū

The glottal stop simply drops in the perfective subjunctive:

Scale IV Perfective Subjunctive: tabrē “become clear”
Person Singular Plural
1st в̄άδ̄βαρι
vāḏbari
в̄ανάδ̄βαρι
vənaḏbari
2nd в̄ατάδ̄βαρι
vətaḏbari
в̄ατάδ̄βαρι
vətaḏbari
3rd в̄είδ̄βαρι
vīḏbari
в̄είδ̄βαρι
vīḏbari

The imperative works as expected: the glottal stop drops in the masculine singular (when word-final), and remains in the other forms:

Scale IV Imperative: tabrē “become clear”
Person Singular Plural
Masculine ταβρεί
tabrī
ταβριού
tabri'ū
Feminine ταβριεί
tabri'ī
ταβριού
tabri'ū

The deverbatives simply lose the glottal stop:

Scale IV Deverbatives: tabrē “become clear”
Infinitive Active Part.
Form μαδ̄βαρή
maḏbarē
μίδ̄βαρι
miḏbari
Meaning become clear becoming clear

8.6.7 C3 = H

Roots with final *H lose this radical and conjugate as though they were biconsonantal, with inherent vowel *ā. The root *zgāh “crazy, mad”, for instance, behaves as though it were *zāg, giving the verb ταζώγ tazāg “go crazy”. These then follow a regular biconsonantal paradigm.

8.6.8 C1 = Y/W

Initial *Y and *W are regular when serving as the syllable onset, but undergo monophthongization when in coda position (with *ay becoming *ē and *aw becoming *ū). The following tables demonstrate the present tense (regular) and preterite (irregular) of two verbs, τηβής tēbēs “dry out” (*ybīs “dry”) and τουσήν tūsēn “fall asleep” (*wsīn “sleep”).

The preterite of τουσήν tūsēn shown above has some irregular endings due to being a C3 = *N verb as well, but the effects of monophthongization can still be clearly seen.

8.6.9 C3 = Y/W

Root-final *Y and *W are preserved when intervocalic and lost in all other positions with no change to surrounding vowels. Shown below, for example, are the preterite forms of ταζμή tazmē “become thirsty” (*zmāy “thirsty”) and ταв̄δή tavdē “become empty” (*bdāw “empty”):

8.6.10 C1/C2/C3 = N

Roots with initial *N (as in *nkīr “recognize”, giving τακκήρ təkhēr “recognize each other”) undergo assimilation when followed immediately by C2, with C2 becoming geminated or aspirated. They are otherwise regular, although if aspiration appears, it will be accompanied by vowel reduction: νατνακιρού natnakirū “we are recognizing each other”, τακκηρνώ təkhērnā “we recognized each other” (not **tankērnā).

Roots with medial *N (such as ταγνήβ tagnēb “sneak [in/out/away]”, from *gnāb “steal”) are regular.

Root-final *N is irregular only in the two past tenses, where assimilation takes place in a number of forms. With the root *lbīn “white” we get the verb ταλβήν talbēn “become white, turn white”:

8.6.11 C1 = PH/TH/KH/TSH/ČH

Roots with initial aspirates are largely unproblematic. Since C1 is always in a cluster, it will always surface in an unaspirated state. The only difference between this and the regular paradigms is that any short vowel immediately preceding C1 will reduce to /ə/. One such root is *phrān “heal”, giving the verb ταπρήν təprēn “heal each other”.

8.6.12 C2 = PH/TH/KH/TSH/ČH

Root-internal aspirates will sometimes surface aspirated and sometimes unaspirated. When intervocalic, the surface realization is always aspirated, resulting in the reduction of the preceding vowel. In other positions, the surface realization is unaspirated, and the conjugation is completely regular. Shown below for reference are the present and preterite tenses of ταλκήν talkēn “kiss each other” (*lkhīn “kiss”, also a C3=N root):

8.6.13 C3 = PH/TH/KH/TSH/ČH

The most irregular aspirate subclass in Scale IV is, naturally, the C3 aspirates, although this irregularity is the same as in other scales. The aspiration will only surface when intervocal, short vowels immediately preceding C3 will reduce to schwa, and the preterite and imperfect use the special set of aspirated endings, plus an epenthetic schwa in some of the second person forms. The chart below demonstrates the conjugation of the verb ταφρήκ tafrēk “get divorced”, from the root *frākh “separate”. Note this this root also contains a C1 fricative, which undergoes metathesis in certain forms.

Scale IV Conjugation: tafrēk “get divorced”
Present Preterite Imperfect Pf. Subj.
1st Sg αφταρώκ
'aftarāk
ταφρήκκετ
tafrēkhet
ταφριήκ
tafriek
в̄ώφταρακ
vāftarək
2nd Sg Masc τιφταρώκ
tiftarāk
ταφρήκκαττα
tafrēkhətha
ταφριήκκετ
tafriekhet
в̄ατάφταρακ
vətaftarək
2nd Sg Fem τιφταρακκεί
tiftarəkhī
ταφρήκκατζζε
tafrēkhəčhe
ταφριήκκες̄
tafriekheš
в̄ατάφταρακ
vətaftarək
3rd Sg Masc ιφταρώκ
yiftarāk
ταφρήκ
tafrēk
ταφριήκ
tafriek
в̄είφταρακ
vīftarək
3rd Sg Fem ιφταρακκεί
yiftarəkhī
ταφρηκκώ
tafrēkhā
ταφριηκκώ
tafriekhā
в̄είφταρακ
vīftarək
1st Pl νιφταρακκού
niftarəkhū
ταφρηκνώ
tafrēknā
ταφριήκκεν
tafriekhen
в̄ανάφταρακ
vənaftarək
2nd Pl Masc τιφταρακκού
tiftarəkhū
ταφρήκκαττυν
tafrēkhəthun
ταφριήκκαττυν
tafriekhəthun
в̄ατάφταρακ
vətaftarək
2nd Pl Fem τιφταρακκού
tiftarəkhū
ταφρήκκατζζιν
tafrēkhəčhin
ταφριήκκατζζιν
tafriekhəčhin
в̄ατάφταρακ
vətaftarək
3rd Pl ιφταρακκού
yiftarəkhū
ταφρηκκού
tafrēkhū
ταφριηκκού
tafriekhū
в̄είφταρακ
vīftarək
Imperative Deverbatives
Masc Sg τιφρώκ
tifrāk
Infinitive μαφταρήκ
maftarēk
Fem Sg τιφρακκεί
tifrəkhī
Participle μίφταρακ
miftarək
Pl τιφρακκού
tifrəkhū

8.6.14 C1 = F/V/Ṯ/Ḏ/S/Z/Š/X/Ǧ

Roots with an initial fricative consonant (excluding /h/) undergo metathesis in forms where C1 comes in direct contact with the prefixed *t marking taktēb verbs. In other words, in the present tense, imperfect subjunctive, and deverbatives, the sequence *-tC1- becomes *-C1t-. Shown below are the present and preterite forms of the verb τασδήρ tasdēr “get ready” (*sdīr “ready”).

Note that despite their usual resistance to such irregularities, this metathesis rule applies to biconsonantal verbs as well.

8.6.15 T-Assimilation

The prefixed *t is especially prone to assimilation in the present tense, perfective subjunctive, and deverbatives, when it comes in direct contact with C1.

When C1 is *T or *D, the prefix will assimilate completely in these forms, resulting in a geminated (never aspirated!) consonant: *dkīr “remember” → ταδ̄κήρ taḏkēr “remember each other” → ναδδακιρού naddakirū “we remember each other” (not *natdakirū).

When C1 is *B or *G, the prefix will voice to *d and then lenite to *ḏ: *gnāb “steal” → ταγνήβ tagnēb “sneak [in/out/away]” → νιδ̄γαναβού niḏganabū “we are sneaking [in/out/away]” (not **nitganabū).

When C1 is a voiced fricative *V/*Ḏ/*Z/*Ǧ, the prefixed *t will first voice to *d and then undergo the usual fricative metathesis: *zmāy “thirsty” → ταζμή tazmē “become thirsty” → νιζδαμαιού nizdamayū “we are becoming thirsty” (not **nitzamayū).

These assimilation rules apply to both triconsonantal and biconsonantal roots.

1) Etymologically-speaking, Barth's Law has no business being here, since this *ta- is not a personal prefix, but a derivational one. However, it seems that it has spread to the taktēb imperative by virtue of the phonetic similarity of the *ta- prefix to the *tV- prefix of the present tense, and the semantic similarity between imperatives (which always have a second person subject) and the fact that *tV- is a marker of the second person in the present tense.