Identical vowels - lengthening
Two identical vowels melt to form one single long vowel (spelled together).
Umlaut formation with a/ā as a leading vowel
a/ā forms umlauts with the succeeding vowel in accordance with vowel increase, Guṇa and Vṛddhi formation (spelled together).
| final sound | initial sound | Sandhi |
| -a/ā | i/ī- | -e- |
| -a/ā | u/ū- | -o- |
| -a/ā | ṛ/ṝ- | -ar- |
| -a/ā | ḷ/ḹ- | -al- |
| -a/ā | e- | -ai- |
| -a/ā | ai- | -ai- |
| -a/ā | o- | -au- |
| -a/ā | au- | -au- |
Formation of semivowels with i/u/ṛ/ḷ
i/u/ṛ/ḷ before are vowel turn into the corresponding consonant/semivowel (spelled together).
| final sound | initial sound | Sandhi |
| -i/ī | Vokal | -y-vowel- |
| -u/ū | Vokal | -v-vowel- |
| -ṛ/ṝ | Vokal | -r-vowel- |
| -ḷ/ḹ | Vokal | -l-vowel- |
Umlauts in front of vowels are dissolved
- "e", "ai" and "o" before vowels (except "e" and "o" before "a") lose their umlaut component (spelled separately, together for compound words).
- "e" and "o" before "a" lose the initial a (spelled together).
| final sound | initial sound | Sandhi |
| -e | a- | -e_' |
| -e | not-a-vowel- | -a_not-a-vowel |
| -o | a- | -o_' |
| -o | not-a-vowel- | -a_not-a-vowel |
| -ai | vowel | -ā_vowel |
| -au | vowel | -āv-vowel |
Vowels in front of consonants - no change
Vowels preceeding consonants remain unchanged. It is only before "ch" that a "c" is inserted (spelled separately, together for compound words).
| Auslaut | Anlaut | Sandhi |
| …Vokal | Nicht-"ch"-Konsonant… | …Vokal_Nicht-"ch"-Konsonant… |
| …Vokal | ch… | …Vokal_cch… |
Exception:
"ī"/"ū" and "e" as final sounds of dual forms remain unchanged, i.e. they are not affected by the rule described above (spelled separately).
In table form
For all of you who like tables and charts - the same information once again in the form of a neat and concise table.
| a/ā | i/ī(1) | u/ū(1) | ṛ (ṝ) | (ḷ/ḹ) | e(1) | ai | o | au | start |
|---|---|---|---|---|---|---|---|---|---|
| ā- | y-a | v-a | r-a | l-a | e_' | ā_a | o_ | āv-a | a |
| ā- | y-ā | v-ā | r-ā | l-ā | a_ā | ā_ā | a_ā | āv-ā | ā |
| e- | ī- | v-i | r-i | l-i | a_i | ā_i | a_i | āv-i | i |
| e- | ī- | v-ī | r-ī | l-ī | a_ī | ā_ī | a_ī | āv-ī | ī |
| o- | y-u | ū- | r-u | l-u | a_u | ā_u | a_u | āv-u | u |
| o- | y-ū | ū- | r-ū | l-ū | a_ū | ā_ū | a_ū | āv-ū | ū |
| a-r | y-ṛ/ṝ | v-ṛ/ṝ | ṝ- | l-ṛ/ṝ | a_ṛ/ṝ | ā_ṛ/ṝ | a_ṛ/ṝ | āv-ṛ/ṝ | ṛ(ṝ) |
| a-l | y-ḷ/ḹ | v-ḷ/ḹ | r-ḷ/ḹ | ḹ | a_ḷ/ḹ | ā_ḷ/ḹ | a_ḷ/ḹ | āv-ḷ/ḹ | (ḷ/ḹ) |
| ai- | y-e | v-e | r-e | l-e | a_e | ā_e | a_e | āv-e | e |
| ai- | y-ai | v-ai | r-ai | l-ai | a_ai | ā_ai | a_ai | āv-ai | ai |
| au- | y-o | v-o | r-o | l-o | a_o | ā_o | a_o | āv-o | o |
| au- | y-au | v-au | r-au | l-au | a_au | ā_au | a_au | āv-au | au |
| a-/ā_X | i-/ī_X | u/ū_X | ṛ/ṝ_X | ḷ/ḹ_X | e_X | ai_X | o_X | u_X | not "ch" consonant |
| a-/ā_cch | i-/ī_cch | u/ū_cch | ṛ/ṝ_cch | ḷ/ḹ_cch | e_cch | ai_cch | o_cch | u_cch | ch |
Exception: "ī", "ū" and "e" as the final sounds of dual forms do not change, also in front of a vowel as the initial sound of the following word. This means that the rule described above does not apply and they remain unchanged (including the separate spelling).