Arabic

laṯaγat- - gum (BK 2 965)

Cf. a variant root laṯˁat-­ ‘the bottom of the lips on the inside, the part of the lips that touches the roots of the teeth’ [BK 2 965]. 

PS
*laṯaγ- - gum (SED I No. 182; Kogan 2011: 222)