க, ச, ட, த, ப and ற are surds ; ங, ஞ, ண, ந, ம and ன are nasals ; and ய, ர, ல, வ, ழ and ள are liquids. The order followed in their arrangement is also that of Sanskrit. To shew that ழ, ள, ற and ன are letters peculiar to Tamil they are placed last.
Quantity or மாத்திரை is different from pronunciation; the one relates to music in poetry, and the other to the enunciation of letters and words in speech. We are not, therefore, concerned here with அளபெடை, prolation or the increase in quantity, which is applicable only to poetry. However, among Tamil vowels இ and உ have sometimes a lesser quantity even in ordinary speech. Sivagnana Swami, the uncompromising critic of இலக்கணவிளக்கம் says, the shortened இ and உ are indicated by a dot; but the truth of his statement is questionable. The dot was never used either in the Tamil inscriptions or in the ordinary writing. Now-a-days a dot is used in Malayalam to denote a final short a which in this language approaches a sound mid-way between அ and உ in (
Tamil characters) ஐ and ஔ being diphthongs, their quantity is shortened at times, the first in all the three places and the second only at the beginning of words. But this does not satisfactorily account for their existence. The semi-vowel ஆய்தம் gets decreased in quantity when words beginning with த combine with words ending in ல் and ள். All these are called சார்பெழுத்து or dependant letters as the changes in quantity occur only in words, but never in isolated letters themselves.
