yaa يا is a harf nida / Vocative Particle that is used to get attention from someone that we want to call. In Latin, it is like lup-e, for example, Et tu Brute!. In Old English, it is like "O", e.g., "O Farid!". In Chinese Mandarin, it is like 啊.
Nb: In Arabic, there are some others vocative particles (huruuf nida). "yaa" is the most commonly used.
If we have really heard "fariid-u", it means the audio attempts to pronounce the ending sound. In Standard Grammar, after يا yaa (harf nida), فريدٌ "fariid(un) /fariid" is spelled as follows:
But, I believe it is an audio glitch because Duolingo tries to omit almost all ending sounds.