For example, speakers of Quebec French often express voiceless alveolar stops (/t/) as an affricate.
This was accomplished by asking Belgian French speakers to repeat an utterance containing this affricate backwards, which resulted in the production of two separate sounds.
An example of allomorphy would be the English plural marker /s/, which can manifest as [s], [z], and [əz] (cats [kæts], dogs [dɒgz], and horses [hoɹsəz]).
An accidental gap is a phenomenon in which a form that could plausibly be found in a given language according to its rules is not present.
[3] In phonology, this is called a phonological gap, and it refers to instances in which a set of related segments containing various contrasts, e.g. between voicing (whether or not the vocal cords vibrate) or aspiration (whether a puff of air is released), is lacking a particular member.
Over the first year of life, infants become less sensitive to those contrasts not found in their native language.
[5][6] Studies have shown, however, that infants do not necessarily pay attention to phonemic differences when acquiring new lexical entries, e.g., 14-month-olds given the made-up labels "daw" and "taw" for new objects used these labels interchangeably to refer to the same object, even though they were capable of perceiving the phonetic difference between /d/ and /t/ and recognizing these as separate phonemes.
These areas are where an individual's talent or lack thereof for pronouncing and distinguishing non-native phonemes comes from.
Take for instance the presence of aspirated and unaspirated alveolar stops that both appear frequently in English, oftentimes without the speaker knowing about the existence of two allophones instead of one.
[citation needed] Bilingual speakers often find themselves in situations where a pair of phonemes are contrasted in one of their languages but not in the other.
There was evidence, however, that by 12 months of age the bilingual infants were able to discriminate the sounds that were contrastive only in Catalan.
Thus, it appears that bilinguals who have a particular phonemic contrast in one of their languages but not in the other are, in fact, able to gain the ability to make the discrimination between the contrasting phonemes of the language that has the pair, but that age and especially input are major factors in determining ability to make the discrimination.