व्यञ्जनानि (Vyañjanāni) are the consonants of Sanskrit. They are 33 in number.
Consonants, when not mixed with any vowel, are hard to pronounce. Hence, they are mixed with a vowel to create a syllable. Consonants can also be joined with other consonants to create conjunct consonants.
There are two main types of consonants- वर्गीय-व्यञ्जनानि (Vargīya-Vyañjanāni), also known as स्पर्श-व्यञ्जनानि (Sparśa-Vyañjanāni) and अवर्गीय-व्यञ्जनानि (Avargīya-Vyañjanāni).
These consonants are 25 in number. They are divided into five groups consisting of five consonants each and they are categorized according to the place where they are pronounced.
In each group, 2 of these consonants are hard (कठोर-व्यञ्जनानि), 2 are soft (मृदु-व्यञ्जनानि) and 1 is nasal (अनुनासिक-व्यञ्जनानि). Also, in each group there are two consonants in which the letter ह (Ha) is not mixed (अघोष-व्यञ्जनानि) and two in which it is mixed (सघोष-व्यञ्जनानि).
Note: The अनुनासिक-व्यञ्जनानि (Nasal Consonants) can be used in the place of the अनुस्वारः (Anusvāraḥ).
When they are used in the place of the अनुस्वारः (Anusvāraḥ), they become परसवर्णाः (Parasavarṇāḥ). The परसवर्णः (Parasavarṇāḥ) of each consonant is the Nasal Consonant i.e. अनुनासिक-व्यञ्जनम् (Anunāsika-Vyañjanam) of its group i.e. वर्गः (Vargaḥ).
This is only applicable for वर्गीय-व्यञ्जनानि (Vargīya-Vyañjanāni) and for an अवर्गीय-व्यञ्जनम् (Avargīya-Vyañjanam), the अनुस्वारः (Anusvāraḥ) will be as it is and no change will occur.
These consonants are further divided into two types- अन्तःस्थ-व्यञ्जनानि (Antaḥstha-Vyañjanāni) and ऊष्म-व्यञ्जनानि (Ūṣma-Vyañjanāni).