Why do the decepticons speak english. I know to humans but why do the speak it when they talk to each other.

 

It's called practicing to speak a foreign language.

 

Um....'cause they want to? 

 

What? 90% of the time they're speaking cybertronian.

 

Because the movie would suck if there were a bunch of scenes where we didn't know what they were saying.

 

because they want to. Theyre 40 foot transforming friggen robots. They can do what they want and nobody can stop them  

 

Because English is one of their mother tounges, infact they taught our anchestors English.

 

But did they teached us how to speak Korean,French,Japenese,German,also include others....and wait.....did WE speak Cybertronian and just traded each other?You're making my confused. and mad 

 

u guys should know this, technically Cybertronnian is English

 

Yes they did, infact, all languages on earth are originally from cybertron.

No, they taught human cybertronian too, but human tounge have big problem pronouncing cybertronian.

 

I agree, there is possibility that cybertronian is english pronounced by fucking metal tounge, after they transform their tounges, they could speak cybertronian heard by us as english.

 

I dunno if they'd need any practice. They probably just download a language file and they're done. But it's still probably useful to know the language of a species you're invading. Perhaps they think if they're overheard speaking Engligh to each other humans might mistake them for Autobots and come closer to get squished.
Really the proper answer is that it's a movie convention when you don't want to bother with subtitles, but that's no fun discussion. There's no real logical in-story answer as Transformers in any English-speaking media have been speaking English to each other since the very beginning, even before they ever came to Earth.

 

Source? Or is this a fan theory?

 

If you click "Spanish" on the DVD, they can also speak Spanish...and French if you click "French".

 

My mind.

This my theory, but I'm not a fan, so this isn't a fan theory.

 

Its for the audiance's sake. Can you imagine watching the scene at the Lincoln Memorial where they explain about Sentinel?

Starscream: Rughtyef geyet nfetrasdod goana! Douyte heosae Sentinel dhy ofterfgah jutear?

Megatron: Hetoga hoee bafiderg nefdea Earth escadulaio teks naoy.

The audiance wouldn't understand it. I'm sure if aliens really did invade they would talk to each other in their own language but not in a movie.

 

This. It's Translation Convention. In-story, they're really speaking Cybertronian, but in order for the audience to understand what they're talking about, it's in English/Spanish/French/etc.

 

Because it beats reading subtitles the whole way thru!

 

Megatron spent decades physically dormant while having to listen to humans speaking (and calling him the wrong name) he probaby doesn't even try, it's just as comfortable to him now as his own language, even if he didn't mean for it. All other Decepticons that follow suit probably speak English out of courtesy to him.