Language of African masseur as he periodically reflects (5)
I believe the answer is:
hausa
'language of african' is the definition.
(Hausa is an African language)
'masseur as he periodically reflects' is the wordplay.
'periodically' indicates alternate letters (letters must be selected 'every so often').
'reflects' shows that the letters should be reversed in order.
'masseur'+'as'+'he'='masseurashe'
The alternate letters of 'masseurashe' are 'asuah'.
'asuah' in reverse letter order is 'HAUSA'.
(Other definitions for hausa that I've seen before include "West African language" , "N. Nigerian tribe" , "N. Nigerian people" , "People of N. Nigeria" .)