Better my English?
My father speaks a bit of English but would like to better it, His native tongue is Bosnian/Croatian/Serbian which aren't offered as languages. Is there any option for him to say hes speaks English but to always choose to learn English?
Unfortunately, there is not. There are no courses on Duolingo related to Serbian Croatian or Bosnian and he cannot both "speak" and "learn" the same language. I'm sorry if I was confused by your question. The sentences are a little confusing.