While RadioReference is based in the US and most of the message traffic in the forums uses American English, posting in American English is not a requirement. The moderators occasionally get reports that a post is in a foreign language. We consider all of those reports to see if there is a problem in context.
Online language translators are readily available. Some modern browsers allow you to highlight text, right click, and pop up a translation.
When you see a post in a language foreign to you, we encourage you to make some effort to translate what you see. If you feel that you can contribute to the thread, please do so in your own language or the OP's language. But, just complaining about posts in a foreign language is not really productive.