Dear Suciati Anandes,

First, you have to make an inventory of certain targeted statements that carefully pose the suprasegmental features you want to investigate . Subsequently, ask the participants (the selected sample) to read them. Naturally, you record their voices in this particular stage. Finally, ask three native speakers of English to rate them based on the accuracy and appropriacy of their production of suprasegmentals. Good luck with your research.

Best regards,

R.Biria

Try recording their voice while they are pronouncing the intended words, u can request at least 2 native speakers 2 rate them, best of luck