Someone ended their sentence with やいな. What dialect is this? What does やい mean? I assume that な means the same thing as in standard Japanese?
Update: the original sentence was 「もう出来あがり？仕事はやいな～」.
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Update: This is not an instance of やい, but rather 速い【はやい】, so the information in my original answer is not actually applicable in this case.
Wikipedia suggests that at the very least, this is a feature of Hakata dialect (though it is also likely a feature of other dialects as well, as suggested by my comment above). In Hakata dialect, it is used as a light suggestion/command, like the ～て form of verbs in other dialect:
な would then be the same as in standard Japanese, as you assumed.
When used not as a suffix, but as a stand-alone word, やい is a (rude) attention-getter among children, like the British "Oi", but specific to kids. (Adults would use おい！)
Kids: やい、俺のガンダムを勝手にいじるな！ (Hey, don't mess with my Gundam toy!)
Adults: おい、おれの新車に触るんじゃねえ！ (Hey, don't touch my new car!)
I believe the above is the most common usage (標準語) usage of やい, though as others have noted, some dialects have their own uses for the word.
PS: I thought I'd answer the question as asked in the title, ignoring the fact that it was inspired by a mis-parsed "速い" :)