The Allophone is the similarity relationship between the variants of a phoneme . Each phoneme can be performed by the speaker differently, resulting in different headphones . Allophones are headphones whose common lines allow them to be associated with a phoneme. The variation in realization can be free or result from complementary distribution. In other words, there are allophones that are phonetically distinctive and there are allophones that are not phonetically distinctive. The different achievements of the vibrant multiple , in the varieties of European Portuguese , are an example of allophony in free distribution.
This means that the phoneme / ʀ / is not phonologically motivated. On the other hand, there are allophones that are contextually motivated, being in a complementary distribution, that is, in the same segment there is only one of the possible allophones. With examples, in the word “car”, the phoneme / ʀ / (third segment) can be performed freely in different ways (free distribution). The phoneme / ʀ / can be apico-alveolar [r], dorso-velar [ʁ] or uvular [ʀ].
Another example, in Brazilian Portuguese, in the words “mel” and “lua” the phoneme allophones  are contextually determined. The phoneme / l / at the end of a syllable or word has a different realization than in cases where the phoneme appears at the beginning of a word or syllable . The phoneme / l / can correspond to the headphones [l] (“moon” [‘luɐ]) or correspond to the sound [w] (“honey” [mɛw]).
Another example of allophones in complementary distribution also comes from Brazilian Portuguese. In the dialects of Minas Gerais and Rio de Janeiro, for example, the phoneme / t / is phonetically pronounced as [t] or [tʃ], depending on the position in which it occurs in the word. [tʃ] occurs in front of the vowel [i] (“tia” [‘tʃiɐ] or “latin” [la’tʃĩ]) and [t] in front of the other vowels (“tua” [‘ tuɐ], “tombo” [‘ tõbʊ]). In this case, both [t] and [tʃ] are allophones or predictable variants (by the context in which they occur) of the same abstract segment, the phoneme (/ t /).Allophony can result in new phonological oppositions, reorganizing the phonological system of a language . It is a common phonetic phenomenon in natural languages.