Yes, everybody does, including you. Many people think of accents as deviations from the norm, i.e. the correct way of speaking. Linguistically, however, we cannot distinguish between correct and incorrect accents as every native speaker’s accent has developed naturally and they are understandable within their speech community. Debating which accent is the most correct is like debating which species of spider is the most correct. The question doesn’t make sense in biology and nor does in linguistics.
Accent is closely related to dialect, or rather, accent is a subset of dialect. Dialect is much broader concerned with all kinds of linguistic differences including grammar and lexis (the words in a language), while accent is just the difference in pronunciation.
We mentioned that all dialects and therefore accents are correct, but the process of standardisation does single out one that becomes the most prestigious spoken by the educated. If all of them are equal, how do we select this standard? Well, it’s completely arbitrary, it is selected by authority. In England, it’s the Queens’s speech. In France, the dialect of the capitol became the standard, in Italy the dialect found in the middle of the country because it resembles that of the south as well as the north. In Germany it is the dialect into which the Bible was translated.
What about foreign accents? Where do they stand among all these “correct” native accents? A foreign accent is fine as long as it is intelligible. I see no reason why someone should work on accent reduction if they are completely understandable. The prestige of a native-like accent or the stigma attached to certain “foreign” accents do make some people want to work hard on their pronunciation to such an extent that it is not necessary any more.
Let’s see some examples of what intelligibility depends on through some phonological examples. Sounds (phones) can be pronounced as allophones of the phonemes of English. A phoneme is a sound in a language that can differentiate meaning. To see which sounds these are in English, let’s look at a minimal pair, two words that are only different in one sound, e.g. bet and bat. These words are only different phonologically in one vowel sound: /e/ in bet and /æ/ in bat, so we know that these sounds are two phonemes. This distinction is important for obvious reasons and this has to be taught to learners of English. In some languages these sounds don’t make any difference and for speakers of these languages it is difficult to differentiate these sounds. A “correct” accent takes into account the difference between these phonemes.
There are many sounds in languages that do not even exist in English or they are allophones in English. To put it simply, an allophone is a variation of a sound that doesn’t give a new word with a different meaning. For example, the “dark l” appears in feel and the “light l” appears in leaf. They are allophones of the phoneme /l/ in English, so they don’t make any difference in meaning and therefore you cannot really hear the difference if you’re an English speaker. In Turkish, for example, the difference is more apparent because they are separate phonemes there. For speakers of English though, it is not necessary to make this distinction, even if they pronounce leaf with a “dark l”, they will be understood. They might not sound native but mixing them up won’t cause any misunderstanding or unintelligibility.
Another example would be the “trilled r” that is very frequent in Spanish but nonexistent in English. A Spanish speaker would intuitively pronounce the [r]s in every English word which would in itself resemble that of most American English varieties (see Rhoticity) but those varieties have a very different [r] sound. However, since it doesn’t make a difference in meaning, it doesn’t matter. The “trilled r” would also be a good alternative to any of the native English [r]s.
Sources and further reading: