Hey Max, just following up here. You would research your competition by first brainstorming some relevant keywords for you niche. The obvious ones to start with would be "How to speak English like an American". If you type that into Google, you'll get a bunch of results and the sites that come up could be your potential competitors.

It looks like most of the sites are educational sites/companies (Wikihow, Preply). There's a site called FluentU which gets into American culture as well.

It's a pretty competitive keyword so you might not want to target it right away, but going over the sites that are already ranking on Google for that topic will give you ideas for additional keywords and directions you can go with your own site.

Then you want to try those keywords (the ones you identify on other sites and ones you come up with) in Jaaxy to see what kind of searches and competition they are getting.

Kyle's training here will give you more idea of what you're looking for and how to find more keywords... Understanding Keywords, The Start of Your Content

I can give you some general tip, first, research competition, audience, how do you plan to monetize your site.. how many articles can you writr on that niche (at least 50 idead).. check all of these before deciding about niche..