Question

By the grace of Allah I have been learning tajweed; what I'm wondering is this: What should I do in my prayer if I notice that I said something wrong in my Tajweed like my letter sounded wrong or I didn't stay long enough on a medd...Should I repeat or am I paying too much attention to tajweed.  I know I'm supposed to be thinking of the meaning.

I would really appreciate an answer to this question.  May Allah reward you greatly. 

Answer

May Allah increase your knowledge of tajweed and grant that you recite the Qur’an as it was revealed to the Prophet, . 

We study tajweed to apply it in our recitation during review, tilawah, and during our prayer.  We should not fix tajweed mistakes during prayer unless we have changed a letter from one to another by changing a characteristic.  If our medd, though, was maybe 3 ½ vowel counts instead of 4, our ghunnah was a little shorter than it should be, or our tafkheem wasn’t at the level it should be, we should not repeat it during our prayer.  This will take away from the meaning as you said, and will be hard on those that may be praying behind you, for they will not know if you are having troubles with your memory or not, and may think you forgot the next aayah. Indeed, the whole concern you are having during prayer may be from the whisperings of Satan, and you may be  in fact, reciting correctly. 

We must fix any word mistakes, or vowel mistakes that are made during prayer, and outside of prayer.  When we are reciting tilawah, reviewing, or memorizing in our home or in a study , situation, we can take the time to correct our mistakes in tajweed and improve our abilities, insha’ Allah this will carry over to our salah. 

Please see this link to understand what is not acceptable in recitation and what is a permissible mistake, and what the answer given here was based upon: http://www.abouttajweed.com/q2060102.htm