Wa `alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Thank you for your question. May Allah accept your prayers and good deeds.
In fact, you should try your best to learn how to offer your prayers as correct as possible. You may need a professional trainer to help you.
Responding to the question in point, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
You should try your best to pronounce the words as correctly as possible. The proper way to go about it is to learn from a scholar. Seeking essential knowledge is an obligatory duty on every Muslim, male and female. Since Salah (prayer) is the most important pillar in Islam, you ought to learn how to pray not from books; rather, from a trained scholar. I am sure you can find one if you look around.
You should know, the first thing that the Prophet (peace be upon him), did with those who converted to Islam was to teach them the basic beliefs and practices of Islam. Once you have this, your minor mistakes are excused.
Allah Almighty knows best.