Salam bro,
My knowledge of Islam is quite weak, as I am a lapsed muslim who is rediscovering Islam.. But I have been reading up a book on Hanafi fiqh on this matter [Hanafi fiqh = Interpretation of basic worship and day to day behaviour according to Imam Abu Hanifah]
You must recite the surahs in arabic, although you can make the duas in English if you like.
The reason for the requirement to recite the salat [obligatory prayer] is because this is how Allah revealed the message and the surahs recited as they were revealed hold so much power and weight.
You should understand also that the salat is very different from the Christian or Jewish prayer, a prayer is when you put your hand up and praise Allah and ask for forgiveness and his blessings, Christians commonly do this before eating food at the table, in Islam we call it dua.
Salat is very different, Salat is extra prayers that the prophets were required to do Muhammad, Jesus, Moses peace be upon them used to pray like that. I'm not very knowledgeable in Christian teachings, but the brother on answering-christianity.com presented some verses from the bible about Jesus "burying his face into the ground to pray to the Lord".. he raised up this verse to explain how Jesus cannot be the Lord if he prostrates down to the Lord to ask for help. Anyways, it is also strong evidence that jesus performed the salat like us as well.
The reason why we muslims have this extra privelage of having the ability to perform Salat, and is required for us to do this is because we are guardians for the revelation, of which there will be no more after prophet Muhammad (saw), therefore no more revelation, and also to be witness to all the prophets, like for instance Jesus will ask the Muslims as witness that he did not teach his followers to worship him and to worship Allah.
Now to answer your question, I can understand how it can be intimidating, however you do not need to pray out loud, in fact you must pray salat quietly, unless leading prayers [which you will not be required to do because the Imam has to be the one with the most knowledge of the Quran an d Shariah].
It is permissible for you to read the surahs from a book during the salat if you do not know the surahs by heart. You can even read the transliteration in English if you do not know the arabic alphabet, but you must strive diligently outside of the salats to learn the Surahs, you only need a handfull. Surah fatehah is compulsury, and then if you want you can learn the short surahs like takasar and nas, which are just 4 sentences..
A concern that reverts may face is that the arabic does not resonate with them becasase they do not understand it, so the best thing to do is while you're studying to memorise the surahs, also get an exhaustive tafseer [translation and detailed analysis, significane, meaning etc of the surahs]