Deidara has a habit of ending his sentences with nasal-like grunts (…うん, …un), roughly translated as "yeah" or "hm".
Sources:
Orginal Song: J. Dash - Wop
Vocal: Deidara (デイダラ)
Anime: Naruto Shippuuden
You can also watch this video on YouTube:
▶️ DTube ▶️ IPFS