Words

Syriac
ṭḥālā - spleen (LSyr. 272, SL 523)
Syriac
tḥiḥ - rotten (LSyr. 820)

tāḥ ‘it is rotten, soft’ (LSyr. 818)

Syriac
tḥumā - limit, boundary, border; precept, regulation, penalty; definition, term (LSyr. 820)

May be an Akkadism, see the discussion and cognates under Akk. taḫūmu 'border, territory'.

Syriac
ṭḥn - to grind (LSyr. 272, SL 523)
Syriac
tḥet - below, under (LSyr. 821, SL 1637)
Syriac
tkel - to believe, to be sure (LSyr. 823)

ap. ‘to assure’, etpe. ‘to be trustworthy’ (LSyr. 823)

Syriac
tkālā - bereveament (LSyr. 823, SL 1644)
Syriac
tekltā - blue-purple colour (LSyr. 823)

Cannot be separated from Akk. takiltu ‘a blue-purple wooľ, Hbr. tǝkēlät ‘a blueish or violet coloured purple wooľ, JPA toklā ‘purple wooľ, CPA twklɁ ‘blue fabric’, JBA tǝkēltā ‘tekhelet color’. Their futher etymology is unknown. 

Syriac
tḳl - to suspend, weigh out, balance (LSyr. 831)
Syriac
tḳn - to establish properly (LSyr. 831)