Practice your Tepehua del Sur. With the expressions from the Lista de Haspelmath : lhiima’alh’ama’ : Pantepec : Puebla/ Click on the blue button that contains the expression you hear in English, with the buttons you can listen to the expression in Tepehua del Sur.
But not only by ear, study them using the button and Praat, record your imitation and let yourself decide when you say it.