3.3.2 Complimentary distribution

　 Sounds like [l], [] and [] that are not found in the same position are said to be in complimentary distribution. The voiceless bilabial stop in pin and the one in spin are in complimentary distribution. They are transcribed as [ph] and [p] respectively. [ph] stands for an aspirated voiceless bilabial stop, [p] an unaspirated voiceless bilabial stop. In English, the two are allophones. Aspiration is also found in team and cool, but not in steam and school. If segments are in complementary distribution (i.e. they do not appear in the same environment) and share a number of features, they are allophones of the same phoneme. Notice that voiceless stops unaspirated after the phoneme /s/ are often mistakenly said to be voiced. Try to pronounce pin, spin and bin, and you will notice the difference. Pronouncing pin, you feel a puff of air rushing out of your mouth, which is not felt in pronouncing spin. In uttering pin, the vocal cords vibrate after the lips are apart, in spin the vibration takes place when the lips are apart, while in pronouncing bin the vibration occurs before the lips are apart. In pin and spin, the vibration is due to the vowel, while in bin, it is first due to the voiced phoneme /b/ and then the vowel.