 Look at the following phenomenon if we gradually cut off the initial fricative in words like spin stick or skin The second phoneme loses its identity So let's do it spin spin spin spin spin spin spin spin spin What is normally regarded as a voiceless plosive consonant seems to become voiced The more portions of the alveolar fricative sir are cut off As a result we cannot differentiate between a voiceless and a voiced plosive in this context anymore The difference between them has been neutralized To combat this problem of neutralization the Prague School of Phonologists in particular Nikolai Trebetzkoi Introduced an abstract unit the archiphoneme It resembles the characteristics of two phonemes which are normally distinct, but cannot be differentiated in certain contexts The spin problem for example where the second segment is neither purr nor burr Could now be handled by means of an archiphoneme Which by convention was assigned a capitalized symbol such as capital P or capital B sharing all properties common to burr or purr and By analogy we can introduce archiphonemes to represent the plosives in stick and skin So archiphonemes are reasonable elements to represent two phonemes that differ in one feature For example in voicing as in the spin stick skin examples or in the German phenomenon of final devoicing