ஃ: While the aytham has been used in grammar text as a vowel sound, now it is commonly used as a mark to indicate sounds not native to the Tamil language. The most popular one being the sound (fa) in words such as 'finance' (ஃபைனான்ஸ்)
conjunct letters: The letters க்ஷ (kssa) ஸ்ரீ (shree) are conuncts that appear very frequently and should be acknowledged as separate from other conjunct matra forms. The க்ஷ (kssa) is a grantha character like ஜ (ja) ஶ (sha) ஷ (ssa) ஸ (sa) ஹ (ha) and is used for Sanskritised text or loan words. ஸ்ரீ (shree) is used in religious contexts or as a honorific title (eg. Shree Ashok Banerjee).
precomposed sign (matra) forms: Changed the semantics of this statement. I want to distinguish between letter conjuncts and combined matra forms as separate concepts.
ஃ ஂ ொ ோ ௌ: included these signs that were a part of the unicode chart.
numerals (tamil) (latin): differentiated the two. The Tamil numerals are not in frequent use today, the Latin numerals are.
௦: Added the Tamil numeral zero.
symbols (unicode): These are necessary symbols for a unicode compliant typeface. Note, ௐ (om) is categorised as a sign on the unicode guidelines.
auxiliary (Tamil supplement): New additions to the unicode block of supplemental Tamil characters.