Editing Tamil script (section)

====Compound form====
Using the consonant 'k' as an example:
<!---
NOTE:
Before editing this page for unicode errors please check your OS configuration for complex character support. You can check it here: http://en.wikipedia.org/wiki/WP:INDIC
--->
{| class="wikitable" style="text-align:center;"
|-
! Formation !! Compound form !! [[ISO 15919]] !! IPA
|-
| lang="ta"| க் + அ || lang="ta"| க || {{transliteration|ta|ISO|ka}} || {{IPA|/kɐ/}}
|-
| lang="ta"| க் + ஆ || lang="ta"| கா || {{transliteration|ta|ISO|kā}} || {{IPA|/kaː/}}
|-
| lang="ta"| க் + இ || lang="ta"| கி || {{transliteration|ta|ISO|ki}} || {{IPA|/ki/}}
|-
| lang="ta"| க் + ஈ || lang="ta"| கீ || {{transliteration|ta|ISO|kī}} || {{IPA|/kiː/}}
|-
| lang="ta"| க் + உ || lang="ta"| கு || {{transliteration|ta|ISO|ku}} || {{IPA|/ku/}}
|-
| lang="ta"| க் + ஊ || lang="ta"| கூ || {{transliteration|ta|ISO|kū}} || {{IPA|/kuː/}}
|-
| lang="ta"| க் + எ || lang="ta"| கெ || {{transliteration|ta|ISO|ke}} || {{IPA|/ke/}}
|-
| lang="ta"| க் + ஏ || lang="ta"| கே|| {{transliteration|ta|ISO|kē}} || {{IPA|/keː/}}
|-
| lang="ta"| க் + ஐ || lang="ta"| கை || {{transliteration|ta|ISO|kai}} || {{IPA|/kɐi̯/}}
|-
| lang="ta"| க் + ஒ || lang="ta"| கொ || {{transliteration|ta|ISO|ko}} || {{IPA|/ko/}}
|-
| lang="ta"| க் + ஓ || lang="ta"| கோ|| {{transliteration|ta|ISO|kō}} || {{IPA|/koː/}}
|-
| lang="ta"| க் + ஔ || lang="ta"| கௌ || {{transliteration|ta|ISO|kau}} || {{IPA|/kɐu̯/}}
|-
|}

The special letter {{lang|ta|ஃ}}, represented by three dots, is called {{transliteration|ta|ISO|āyta eḻuttu}} or ''aḵ''. It originally represented an archaic Tamil retention of the Dravidian sound ḥ, which has been lost in almost all modern Dravidian languages, and in Tamil traditionally serves a purely grammatical function, but in modern times it has come to be used as a diacritic to represent foreign sounds. For example, {{lang|ta|ஃப}} is used for the English sound ''f'', not found in Tamil. It also served before palm leaves became the primary writing medium for words ending with an inherent consonsant-vowel ''u'' as a pronouncing rule for a short ''u'', called''{{Dash}}''{{Langx|ta|குற்றியலுகரம்|lit=short 'u'-sound|translit=kuṟṟiyal-ukaram}}. Following consonants rendered this behaviour: {{lang|ta|கு}}, {{lang|ta|சு}}, {{lang|ta|டு}}, {{lang|ta|து}}, {{lang|ta|பு}}, {{lang|ta|று}}. Instead of writing like in modern days without any markers, for example ({{Langx|ta|அது|translit=Atu}}), it was written with a preceding {{lang|ta|ஃ}}, like {{Dash}} {{Langx|ta|அஃது|translit=Aḥtu}}.

Another archaic Tamil letter {{lang|ta|ஂ}}, represented by a small hollow circle and called {{transliteration|ta|ISO|Aṉuvara}}, is the ''[[Anusvara]]''. It was traditionally used as a [[homorganic]] nasal when in front of a consonant, and either as a bilabial nasal ({{IPA|m}}) or alveolar nasal ({{IPA|n}}) at the end of a word, depending on the context.

The long ({{transliteration|ta|ISO|nedil}}) vowels are about twice as long as the short ({{transliteration|ta|ISO|kuṟil}}) vowels. The [[diphthong]]s are usually pronounced about one and a half times as long as the short vowels, though some grammatical texts place them with the long ({{transliteration|ta|ISO|nedil}}) vowels.

As can be seen in the compound form, the vowel sign can be added to the right, left or both sides of the consonants. It can also form a [[Ligature (typography)|ligature]]. These rules are evolving and older use has more ligatures than modern use. What you actually see on this page depends on your font selection; for example, [[Code2000]] will show more ligatures than [[Latha (typeface)|Latha]].

There are proponents of script reform who want to eliminate all ligatures and let all vowel signs appear on the right side.

Unicode encodes the character in logical order (always the consonant first), whereas legacy 8-bit encodings (such as [[TSCII]]) prefer the written order. This makes it necessary to reorder when converting from one encoding to another; it is not sufficient simply to map one set of code points to the other.