Is it okay to use british english but speak with american accent?

Where? In Britain? I assume they would just think you are an American. Learning the British usages of biscuits and boot and pants and such would just be you using the vocabulary that is most clear in the location you are in. In America? You'd either mildly confuse folks with the alternate vocabulary, or you'd come across as either weird or pretentious. A reasonable number of folks would understand you, because British TV shows and movies are popular here, but it would come across as odd to talk about buying petrol for your lorry instead of buying gas for your truck.

As an ESL speaker? I would imagine it's fairly common in countries that teach British English grammar and vocabulary but where the accent is mainly picked up from American TV and movies. As a native speaker? It would be weird to affect an accent that isn't your own, but it's perfectly normal to switch between US and British English when writing, depending on the audience.

I mean… sure? But I’m not sure what the advantages of this would be. Why not use a British accent if you’re going to be speaking in a British context?

I grew up living in England with American parents. I spoke American English with a British accent for years, so the opposite of what you are asking. People will think it's weird, but they will still understand you. There are not very many differences between British and American English, and Americans can still usually understand British English words without difficulty

I would say, for a lot of learners, getting a mix of the two most prominent varieties of English is pretty normal.

Absolutely not; that would be a blatant betrayal of your homeland. You're pretty much guilty of treason at that point. /s

I think that’s called Canadian /s

Of course it's okay. But depending on the exact situation and how locale-specific you get with your vocabulary, it might confuse someone. I (an American) use several somewhat outdated British words and phrases in my speech because of the influence of a favorite author. For example, you'll often hear me say "Hullo!" as an exclamation.

In Britain, nobody would notice or care about your accent. In America you might face some confusion or even hostility in some contexts if you use British rather than American terminology. As a Brit, I’m obviously biased towards British English, but for an ESL learner, it’s probably easier to default to American English unless you’re planning to move to the UK. American English is what most non-native speakers learn, so it’s the most useful in conversing with other ESL speakers and keeps the Americans quiet.

That’s me! I’m glad someone asked this question! Speaking in an American accent (so to speak) is easier cause it doesn’t sound right for me to drop the R sound (I mean it’s there, why not pronounce it? Jk) but I use British English as I live in Europe where its influence is stronger than of American English, plus I prefer the BrE vocabulary.

You’ve basically described Canada lol

Yes, but it also depends where and around whom.

You can do whatever you want but people would reasonably find this strange, if that means anything to you.

It’s okay to be Canadian.

My 8 year old nephew does this (picked up from his favourite YouTubers). It’s a little jarring sometimes but meh who cares

It’s best to use whatever is local to where you are, but it’s not that big of a deal and there aren’t that many differences between American and British English anyways

I don't see anything wrong with it, I've been in Australia for a bit and use their slang but I don't have an Aussie accent

As a non-native english speaker, I mix up the accent and the vocab a lot and all the time.

No one is stopping you, but some might find it odd, or you might experience some miscommunication. Just imagine someone with a regional American accent asking another American if he has a rubber (eraser), and a fag(cigarette). Without the British accent, one might misunderstood. Or if you tell someone to meet you on 2nd floor. (The accent gives a bit of an idea what vocabulary one might use).

No, only Indian accent please

True story. Grew up in America partly. Traveled a lot. Speak French. Attended British school one year. Result. Always have to double-check spelling. Color, colour, and couleur are a problem.

No they will kill you. Yeah of course people have no right to be fuming for that.

A lot of Americans have picked up some British phrases but don't use a British accent to say them.

Americans would find you pretentious.

Not sure why you got downvoted for this. Honestly - if you have even the TINIEST bit of an accent that gives away you're an ESL speaker, most people will think nothing of it. If you had absolutely zero accent and were mistaken for a native speaker, at worst someone might think you're a slightly pretentious Anglophile.

Absolutely not. You will go straight to jail.

People will just think you're Canadian

Sure, though it might sound odd to some. I sometimes use "anticlockwise" instead of "counterclockwise" because I like the way it sounds better, but I wouldn't be shocked if someone was a touch confused by it.

My English professors used to tell us to choose one of them, never mix them. If you use British vocabulary then try to practice the accent as well and vice versa. It’s not like there’s a written rule for that or anything but it would be weird and confusing since it’s not a “natural” thing to do.

I mean accents aren't right or wrong. American english just is wrong.

People might think you're weird if you use an American accent but british terminology.