The modern Dzongkha writing uses the alphabet system first introduced by Thonmi Sambhota. Son of Anu of the Thonmi clan from central Tibet, Sambhota was the most intelligent minister of the religious Tibetan king Songtsen Gampo (Srong-btsan-sgam-po). He was believed to be an emanation of Manjushiri, the Lord of wisdom. The king sent Sambhota with fifteen other young Tibetans to study Sanskrit in India. Sambhota studied linguistics at the feet of Pandita Devavidhayasinha and Brahmin Lipikara of Kashmir. Since he was the brightest student, his teachers called him "Sam-bhota" meaning "best Tibetan".
After mastering linguistics in India, Sambhota went back to Tibet and introduced the Tibetan alphabet system along with king Songtsen Gampo which comprises of thirty consonants and four vowels. The sound system and the structure of the alphabet were based on Devanagari, a script used for many modern and older languages of India, including Sanskrit, Hindi, and Nepali. Although the writing system (namely Jogyig) was brought to Bhutan by Dematsema (ldanma-Tsemang) on the invitation of Sindhu Raja, the origin of the Bhutanese alphabet has to be traced back to Sambhota since the jogyig is also based on his alphabet. Initially, Sambhota wrote eight aspects of Tibetan grammar but only two - Sumchupa (sum-bcu-pa) and Takijugpa (stags-kyi-yjug-pa) are extant today.
For this reason, Dzongkha grammar is one of the easiest as opposed to the universal claim that it is too complicated and hard to comprehend. Other languages have all these aspects of grammar or more but Dzongkha is condensed into these two, making it comparatively easy to understand and remember.
The thirty consonants of Dzongkha alphabet, traditionally called selje sumchu (gsal-byed-sum-bcu), are classified into seven groups of four and one group of two (the last two letters ha and ah) according to yigui kye ne (yigei-skye-gnas) "place of articulation". Most of these sounds are produced by a pulmonic egressive airstream mechanism, i.e., sounds are mostly produced by pushing out air from the lungs.
Most of the manners of articulation are carried out by the tongue with other organs such as labial (lips), dental (teeth), hard and soft palate, velum, glottis, and so on. Because of the lack of such biological terms for most of the body parts in Tibetan, all the consonant groups are named with the initial letter of the group such as Ka-de (ka-sde) "Ka-group" for the first four letters ka, kha, ga, and nga, Ca-de (ca-sde) "Ca-group" for the second four letters ca, cha, ja, nya, and so on. For manners of articulation, activities are carried out by means of nangdu threpa (nang-du-phradpa) "internal touching", cungze threpa (cung-zad-phradpa) "slight touching", tsumpa (btsum-pa) "closing", and chewa (phye-ba) "opening". These traditional linguistic terms indicate that the lack of labels did not prevent Sambhota from identifying the mechanism and manner of articulating these consonants and vowels.x
Modern linguistics analysis show that there are reasons why Sambhota kept ka, kha, ga, and nga in one group, ca, cha, ja, and nya in another group, ta, tha, da, and na in yet another group, and so on till ha and ah. This is because the first four letters - ka, kha, ga, and nga are called velars. They are produced by raising the back of the tongue to the soft palate or velum.
The second four letters - ca, cha, ja, and nya are called palatals because they are produced by raising the front part of the tongue to a point on the hard palate just behind the alveolar ridge.
Ta, tha, da, and na are called interdentals (between the teeth) as they are produced by inserting the tip of tongue between the upper and the lower teeth.
Pa, pha, ba, and ma are called bilabials since these sounds are articulated by bringing both lips together.
Likewise, tsa, tsha, zra, wa, zha, za, oa, ya, are called fricatives and affricates depending on where and how they are articulated. Ra and la together are called liquid sounds. Specifically, ra is called rhotic and la is called lateral. In producing ra sound, the tongue tip is raised to just behind the alveolar ridge and therefore it is also called alveolar glide. In the production of lateral sound la, the front part of the tongue makes contact with the alveolar ridge, but the sides of the tongue are down, permitting the air to escape laterally over the sides of the tongue.
Sha and sa are called fricatives. In the production of these sounds, the airstream is not completely stopped but is obstructed from flowing freely. When you utter these two sounds, you will feel the air coming out of your mouth. The passage in the mouth through which this air passes is narrow causing friction or turbulence.
The last two letters - ha and ah are called glottals. In producing these two sounds, the glottis is open and no other modification of airstream mechanism occur in the mouth. The air is stopped completely at the glottis by closed vocal cords.
So, we see that Sambhota has arranged the thirty consonants into groups in order of their place and manner of articulation.
The consonants are also classified according to their manners of articulation such as ug chewa (dhugs-che-ba) "voiced", ug chungwa (dhugs-chung-ba) "voiceless", drathoen chewa (sgra-thon-che-ba) "hard sounds", and drathoen chunwa (sgra-thon-chung-ba) "soft sounds". Analysing phonetically, such letters as pa, ta, ka, and sa in Dzongkha are voiceless sounds (dbugs-chung-ba).
In producing these sounds, the vocal cords are apart when the airstream is pushed from the lungs. The air is not obstructed at the glottis, and it passes freely into the supraglottal cavities. Because of this, they are called voiceless sounds.
On the other hand, such letters as ba, da, ga, and zra in Dzongkha are voiced sounds (dbugs-che-ba) because when these sounds are produced, the vocal cords are together and the airstream forces its way through and causes them to vibrate. Hence, they are called voiced sounds.
by Pema Wangdi,