Tongue? Hold it, with oxtail initially not available (5)
I believe the answer is:
shona
'tongue?' is the definition.
(a language of Zimbabwe)
'hold it with oxtail initially not available' is the wordplay.
'hold it' becomes 'sh' (both can mean to tell someone to stop speaking).
'with' says to put letters next to each other.
'initially' says to take the initial letters.
'not available' becomes 'na' (abbreviation for not available).
The first letter of 'oxtail' is 'o'.
'sh'+'o'+'na'='SHONA'
(Other definitions for shona that I've seen before include "Scotswoman'" , "African language" , "Language of southern Africa" , "foreign language" , "Member of a Bantu people living in Zimbabwe" .)