that one really wasn't fair! I checked the hover hints for t-shirt, and it just said شيرْت, so I thought they must have the same word for both shirt and t-shirt!! Not cool, Duo! ;-)
The vocative case is being overused. I rarely hear يا from native speakers.
Because this is probably fus-ha arabic (formal arab)
İ agree with you
th fact why "T" and "shirt" has to be separated ?