How to pronounce an Arabic letter when it takes Fat'ha on it?
For example if the Noon letter takes a fat'hah should v pronounce as "Na" like in "Nut" or "Ne" like in "Partner"?
Another example, if the letter Baa take a fat'hah should v pronounce as "Ba" like in "But" or "Be" like in "Fiber"?
We strongly recommend that you do not try to compare the Arabic vowels and letters (for the most part) to English vowels and letters. The world is full of different dialects in English and the way a person in one town- not even country-pronounces an A or a U or a E can be very different than another town. Comparing Arabic vowels to English vowels thus causes mispronunciation and confusion for the student of the Qur'an.
For this reason we need to listen to correct recitation from a qualified mastered teacher of the Qur'an and imitate them to learn the correct sound of the vowel.
We suggest listening to the recordings of Sheikh Ayman Swayd, may Allah preserve him.
You may listen to his recitation of surah al-Baqara at the following link:
Surah Aali 'Imran:
Many or most other surahs: