Help changing the language on my iPhone please

Ever since I have been using this particular phone( which I bought just to replace my old lost phone) every time my phone dies and I try to turn it on (because I don’t know that it’s dead at this point) it shows the picture of the charger and the battery with red in it to show that it needs to be plugged in which is normal but it also says “ iPhone is findable” or something almost exactly like that. On my other phones in the past it would say “iPhone is dead”, something about plugging it in or something else along those lines but always in English! I’m trying to figure out why it’s in Swedish or some other language now and most importantly HOW do I fix it? Thankfully I have only noticed this language issue in the situation that I described here. But I’m worried that other areas may have been(or will be) affected and I just haven’t noticed it yet. This would cause a huge problem because I need everything to be written in proper English to be able to understand what I’m reading. So please could somebody let me know what I need to do to fix this problem and how I can stop it from happening again in the future? Step by step directions how to go about fixing it would be optimal and greatly appreciated. Thanks in advance to anybody who takes the time to help me with an answer!