SomeCallMeChris Wrote:So, です and だす prove that there are at least two vowels in Japanese to differentiate the 'e' and the 'a', and (we are assured) if we keep doing this for all the words in the Japanese language, we find that only 5 vowels are required?
Exactly.
Let's say you asked 100 people to say the a in だす and you had VERY precise instruments to measure the results (probably in the form of a sound wave). You'd probably find 100 different results. In fact, you'd probably find 100 different results if you, yourself, said the same vowel 100 times. However, you'd also find that all of those sounds meet certain criteria which, to the ears of native speakers of the language, qualify them as the same vowel. The sounds of human languages are such that a certain degree of variation is allowed to ensure comprehension between individuals.
In the case of vowels, it's a bit as if they each occupied a small space in the mouth, like a bubble. The sound can move around that space and keep its identity, but once the boundaries are crossed, the sounds become ambiguous. In languages with more vowels, an error often means you've said a different vowel as the space between them is much smaller. The space given to the vowels of each language differs, and so the space of one vowel in language A may partly cover the space of 2 vowels in language B. In the case of dialects within the same language, the spaces have often shifted a bit, but their relationship to one another remains consistent. It's also natural that over time, say over centuries, these spaces inevitably move, shift and vary in every language.
Apart from space, vowels also vary in several features such as length, nasality, tension, etc., and again, whether these features are distinctive or not will depend on the language. For instance, vowels can become nasal in English and Japanese when a nasal consonant follows (cf. bank, shinbun), but not in French or Portuguese because nasal vowels are a distinct set of vowels.
This is roughly how phonetics (which measures the exact sounds made) can indeed reveal that speakers make a lot of different vowel sounds, while phonology (which groups all these sounds' features to identity the few units that we call vowels) will conclude that languages like Japanese and Spanish only have 5 distinct vowels.
Edit: Fillanzea explained mostly the same thing, but using the basket image. Neat!
Edited: 2012-03-20, 6:24 am