g for ganga

g for ganga
கங்கா - Ganga(Ganges in English) is a trans-boundary river between India and Bangladesh.

Varanasi/Ganga

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க-ga/ka
ங்=ng
கா=gaa/kaa
In this case, the consonant represents the sound ga in both the starting and ending of the word. As mentioned earlier while compared to other Indian languages which have 36 consonants Tamil has only 18. So some alphabets are used for two sounds. க is one such consonant. It has ka sound in words like kaadu(காது), kann(கண்) while in words like ganga it has a ga sound. Tamil has no capital letters or running handwriting. The letters are always written separate and there are no conjuncts like other Indian languages. So it is an easier language to learn compared to other Indian languages. But to know how the words sounds like whether it kaadu or gaadu, you have to by heart the word and I think there are no hard and fast rules. Most of the words which start is க have it sound as ka rather than ga.
க - >கா
ka->kaa
while the vowel sign is shown by removing the dot from the consonant, for the long aa vowel it is written seperately as shown below.
க் -  க  - கா
ik - ka - kaa
The other translieration, vowels and vowel signs for ka are shown below
 a          aa        e    ee    u        oo        e      E      ai      o       O         au
அ ஆ இ ஈ உ ஊ எ    ஏ   ஐ   ஒ       ஓ     ஔ 
க  கா கி கீ கு கூ கெ கே கை கொ கோ கௌ

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