Native speaker
In Emirati Arabic, “When?” is متى؟ (mitaa?).
متى؟
When?
It's in the phrasebook under Yes, no & everyday basics, with 90 more like it.
wayn?
khatar
shlohn?
maa bee
tabee imsaa'da?to a man
abee
Source: DLIFLC Emirati Basic Language Survival Kit (2007). Credits and licences