The pronunciation of a foreign language is very difficult. But we can learn it and improve it through practice. Whenever you want to know how to pronounce a word, you can try a dictionary online, like the Merriam Webster Dictionary. There you can find the meaning of words in English, a Spanish-English Dictionary and even a Medical Dictionary.
If you want to practise the sounds of the English language in isolation you can try this site. Here you can listen to the sounds of English as many times as you want to and even select if you want these sounds pronounced by a man or a woman.
In any case remeber Pili’s post “Pronunciation is really important“.