¹ There are no dental fricatives in Sanskrit, yet, oddly, IAST (the standard transliteration scheme) uses a 'v' rather than a 'w' to represent the labial sound 'va'.
Categorisation of vowels and consonants
Sanskrit vowels and consonants fall into one of five categories:
Gutteral - pronounced from the throat a, ā, ka, kha, ga, gha, ṅga, ha
Palatal - pronounced from the palate i, ī, ca, cha, ja, jha, ña, ya, śa
Cerebral - pronounced from the cerebrum ṛ, ṝ, ṭa, ṭha, ḍa, ḍha, ṇa, ra, ṣa
Dental - pronounced from the teeth ḷ, ta, tha, da, dha, na, la, sa
Labial - pronounced from the lips u, ū, pa, pha, ba, bha, ma, va
Two consonants in each category are aspirated, two are not, and one in each is pronounced nasally. Three of the five categories have a sibilant. Each category has a vowel and a semi-vowel.
Consonants
Consonants, whether aspirated or unaspirated, are by convention listed using the vowel 'a' (as in the above chart). Only vowels 'shine' independently whereas consonants, having no sound, need a vowel in order to be spoken – hence the name consonant, 'sounding with'.
Aspirated and unaspirated characters
Aspirated Sanskrit consonants are uttered with mahāprāṇa, a deliberate, brisk expelling of air. The aspiration is shown by the inclusion of an 'h' before the vowel (ha, gha, cha, jha, ṭha, ḍha, tha, dha, pha, bha).
Their unaspirated forms (ka, ga, ca, ja, ṭa, ḍa, ta, da, pa, ba) have neither that 'h' nor the brisk breath of air before the vowel. They are alpaprāṇa, they are spoken with no deliberate expelling of air.
Anusvāra - Nasalised sound
Five sounds ṅa, ña, ṇa, na and ma are uttered with nasalisation. The relevant nasalised sound can be represented in transliteration by an anusvāra, chiefly an 'm' with a dot below ṃ – but, in a few special instances, with a dot above ṁ.
Sibilant - A hissing sound
Three sounds śa, ṣa and sa are sounded respectively like the English words 'hush!', 'shush!' and 'hiss', but ṣa is sounded by arching the tongue slightly, towards the cerebrum.
Semi-vowels
The four semi-vowels ya, ra, la, and va are sounded by immediately following one vowel with another: 'i' followed by 'a' forms 'ya' 'ṛ' followed by 'a' forms 'ra' 'ḷ' followed by 'a' forms 'la' 'u' followed by 'a' forms 'va'¹ The sound 'ha' is a special form of semi-vowel in which breath alone precedes the vowel.
Visarga - An aspiration that reflects the immediately preceding vowel
An 'h' with a dot below (ḥ) denotes a visarga. A visarga indicates that the immediately preceding vowel should be reflected in an aspiration of air. So, if the vowel is 'a', the breath in a visarga reflects the 'a' and the 'a' becomes aha. If the vowel is 'i', the breath in a visarga reflects the 'i' and the 'i' becomes ihi.
Hence, nara plus a visarga (naraḥ) is pronounced naraha, and pati plus a visarga (patiḥ) is pronounced patihi, and prabhu plus a visarga (prabhuḥ) is pronounced prabhuhu.
Conjunct consonants
Sometimes two consonants are made adjacent, with no intervening vowel. This is known as conjunction. For example, kṣa is the conjunct of ka and ṣa, and jña is the conjunct of ja and ña. The vowel in ka and ja disappears in forming the conjunct.
