What is the difference between -amazsın and -amıyorsun?

When do you use either one?

Is there any forum topic on negative ability / can-can´t?

http://www.turkishclass.com/turkish_lesson_314

-amazsın (geniş zaman)

-amıyorsun (şimdiki zaman)

Thanks for the link. It´s making me cry, but thanks

 -e/a + mez + personal suffix    ----> emez / amaz

 - e/a + me + iyor + personal suffix ---> emiyor / amıyor

Most of the time, these two forms of ability are not interchangeable.

However, there are some clues which may help you to choose the right usage:

* when you want to emphasize something you are not able to do especially at present time,  -emiyor/amıyor may fit good to use:

- İstanbul´a gidemiyorum. ---> I am not [being] able to go to Istanbul [currently,at present time]

- Artık dayanamıyorum. --> I can´t [ I am not being able to] bear with this anymore [something that you think you can´t stand/bear anymore [at present]

* Something you strongly/strictly  belive that something CAN NOT happen for some reasons.

- Istanbul´a gidemem ---> I can not go to Istanbul [ since I have no chance at all / I have no place to stay there / I have no opportunity to go to Istanbul etc..]

* Burada kalamam ---> I can not stay here. [Since I have no chance to stay here/ This is not kind of place that I can stay/ I can not stay here because there is somebody I don´t like here etc..]

* Unlike English, using present form fit better for regular/habitual acts.

-Sabahları erken kalkamıyorum. ---> I am not [being] able to get up early in the mornings. ---> habitual act

- Geceleri erken yatamıyorum.  ---> I am not [being] able to go to bet at nights.---> habitual act