Can anyone please help me and clearly explain the difference between the 3 ability words

dai ได้

pen เป็น

wai ไหว

Thanks a lot.

This may help you to understand their usage:-

in a negative ways

ได - ไปไม่ได can't go, not free.

เป็น - ว่ายเไม่ป็น can't swim, don't know how to swim.

ไหว - รอไม่ไหวแล้ว can't wait any longer, can't bear to wait any longer.

To differentiate between dai ได pen เป็น think of it like this: with dai something may be preventing you from doing something, with bpen you are lacking the ability to start with. As far as wai goes this is more like physically unable.

Some examples:

ลดราคาไม่ได้ Can't reduce the price

พูดภาษาอังกฤษไม่เป็น Can't speak English

เดินไม่ไหวแล้ว Can't keep walking

Thanks lads. Am I right in summing up that:

dai ได้ = I can do this if I so wish

pen เป็น = I have already learned this and am skillful at it

wai ไหว = I am physically able and strong enough to do this