What causes bilinguals to have/not have accents?
I know people who have been in the US for 20 years and they still have accents. I know other people who've been here less than 10 and have virtually no accent. These people are mixed ages and mixed ethnicities (mainly Spanish, Italian, Russian, Polish, French, Croatian).
why is this?
Every language has a different set of sounds that make up all of the sounds in that language. When you learn to speak a new language, you have to deal with a set of sounds that is not the same as the one in your native language. There are also rules about when certain sounds can appear in words. These rules are often different between languages. When you pronounce words in a language using sounds that don't appear in that place in that language, using instead the sound rules from your native tongue, you have an accent. You lose your accent by learning to make the correct sounds in the correct places, like a native speaker does. The degree of success you have in losing your accent depends on a number of factors, but it's different for everybody. Just as people learn grammar and vocabulary at different speeds, people learn correct pronunciation at different speeds.
Everybody has an accent. Do you mean 'foreign' accent?
Acquiring a native accent in adulthood is a matter of practice, attention and to some degree, talent. I pushed out my native accent after years of jokes at English schools through sheer force of will, but it comes out when I'm stressed. Other people assimilate naturally, without thinking about it.
Those who've been bilingual since birth don't learn the second language through another, hence they don't have a distinctly foreign accent. Some people learn to speak an accent native that is native to the language they study. Some people choose not to do so, or choose to mainly speak with a foreign accent despite knowing multiple accents, for a multitude of reasons.
That's right! For example, a baby growing up a native speaker of both English and French isn't learning "English for French speakers" and isn't learning "French for English speakers." That child is learning English for babies learning a first language and French for babies learning a first language. :)
Children below the age of nine immersed in a new culture can acquire a second language with a flawless native accent. Language learning methods like Pimsleur which rely exclusively on listening and oral repetition without reading are proabably better for replicating a native accent. Unfortunately most of us adults enjoy reading in our acquired languages and build a much larger vocabulary this way...at the expense of our pronunciation.
The sound systems of native languages obviously play a role, but clearly people with the same native language can have a great diversity of accent "thickness." Some people just have an ear for sound distinctions; I think skilled singers can have a leg up here. I've come across native English speakers who were good singers who could read Spanish with a much less grating accent, despite knowing only a tiny amount of Spanish, than other English native speakers who were fluent, or could at least hold a conversation, in Spanish.
And some of it is just effort. One of my good buddies is Spanish, lived in the U.S. for years, knew how to pronounce (most) English words well, but just found it required too much effort or concentration or something to bother with it on a routine basis.
Linguistically speaking, everyone has an accent. Even the term "foreign" accent is a misnomer. It might be a different accent rather than a "foreign" accent. It is all a matter of perspective. To a native Canadian, a Brit has a "foreign" accent. It is simply a different accent.
What you're saying is besides the point and it's a misnomer to call it a misnomer. It's a misnomer to call a foreign accent a misnomer since the term "foreign accent" points to a "different accent compared to where you are" = a variable, not a constant. This shouldn't even be a point of discussion since the obvious word "foreign" in "foreign accent". A word having a variable meaning doesn't make it a misnomer!!! When I go to China and say "I'm in a foreign country" it's not a misnomer. Or a different example, the variable "my". "My car" might be different to me compared to what "my car" is to you, but it's still not a misnomer.
It's about local (~country level) versus non-local / foreign accents^. "Everybody has an accent" is true but also a strong oversimplification. Take i.e. a local accent, you've got people who try to speak with an as strong of a local accent as possible while others will only minimally have that same accent.
^ Obviously you're also able to spot the common ground between a Brit in Canada and a Canadian in the UK. What they have in common? They have a foreign accent compared to the local accent.
Isn't an accent simply the set of differences between how the speaker pronounces things and the listener pronounces things?
For example, I can't hear my own accent and someone with the same native dialect as me wouldn't hear an accent when I speak either.
Likewise, when a native speaker of U.K. English hears me, he or she will hear the differences between how I speak and U.K. English as "an American accent."
When a native speaker of Cantonese hears me, he or she will hear the differences between how I speak and Cantonese as "an American accent."
The thing is, the differences between how I speak and U.K. English and the differences between how I speak and Cantonese probably aren't exactly the same as each other! ;)
By effort and by choice. If you don't try to make your accent go away, it won't (completely) go away. If you do put some effort into it and try to look out for it, you'll be able to lose it. It's just like Americans speaking with a strong local accent (or any other country), they could lose it if they'd want to, but they won't if they don't want to.
When you're fluent in a language, your accent is mainly decided by choice, one that is made both knowingly and unconsciously (i.e. peer pressure). For example there are many people who have very strong local accents, mainly by choice. They're able to speak with less of an accent without any effort, but they choose not to.
When learning a language at a young age no / less effort will be required since you're a lot more likely to have less of a foreign accent from the get-go.
Personally, when learning a foreign language I don't care about accents. I prefer to learn to speak the language correctly as neutrally as possible ("no" accent). For example, Portuguese, I don't care about having a Brazilian accent, I prefer to just pronounce everything correctly and be understandable.
It may well take more than "some effort" it seems to me. For instance, my accent is a fairly standard version of General American, but now I live in an area affected by the Northern Cities Shift, so not having that myself, here I could be considered to have an accent. Thing is, the Northern Cities Shift to me mainly seems like a bunch of wrong vowels popping up in random places. I've lived here for years and don't know how it works. Also, I have the cot-caught merger; this area doesn't. And goodness help me if I try to discern the minute difference that people here produce automatically. It's a whole different animal than where /ɑ/ and /ɔ/ fall on the IPA chart.
In order to create the sounds of another language, it's necessary to use your tongue, your lips and even your jaw differently. Even sounds like 'p' and 't' change slightly between languages. I had an American friend in France years ago who spoke perfect French after working really hard at University. Her face changed completely when she spoke French; she didn't look the same. The problem of eradicating an accent is in some way morphological.