The Mātrikā Chakra consists of thirteen Vowels or Svars; twenty-five Mutes or Sparsh; four Semi-vowels called Antaḥstḥaḥ and the Sibilants or Uṣhman – the Shaktī symbols. The letters ‘sh’, ‘shh’ & ‘sa’ are the first three sibilants. The fourth is ‘h’ that, as we have seen, is the aspirate and represents the prāna.
The Svars or Vowels are the ‘pure sounds’ and derived from ‘svarna’ or gold, they are the ‘shining sounds’. The Vowels are likened to the energies of the day and the consonants to the night. The ‘a’ if suppressed, and treated as the Unknown, the Unseen Brahmn it leaves us with 12 signs. These are the number of months or the sun-signs. ‘a’ is further embedded as a suffix in every mute and sibilant directly  and in the semi-vowels inherently – thus it constitutes every spoken word, sentence and gets integrated into the very fabric of all that shall be named in our conscious Universe.
The ‘h’ sound is also present in every alternate Mute or Sparsh, leaving the Anunāsiks or Nasal-stops. Of these twenty balance Sparsh (ka, kha, ga, gha, cha, chha etc.) the ten without the aspirate are alp-prāna, while the ones with the aspirate are called māhā-prāna. The primary svars are ‘a’, ‘i’, ‘u’, ‘ri’ & ‘lri’. (The latter is rarely used in literature). The first three ‘a’, ‘i’, ‘u’ are the fundamentals since to pronounce them the tongue is not deflected. (The same is true also for the aspirate ‘h’). ‘ri’ and ‘lri’ are half-way between vowels and consonants since the tip of the tongue is used in pronouncing them. In fact the Śiva Sūtras  terms these two vowels as ṣhandaḥ or eunuchs. All these five vowels are of single sound i.e. of one mātrā. As these mātrās or long and protracted sounds come into play, the chhands are formed and we will look at these again later.