Most of the world’s scripts are used in India and Southeastern Asia. Nearly every respectable language has its own script in this region. All Indian/Southeast Asian scripts are however quite similar to each other.
All are written left-to-right.
”Minor scripts” may seem to be a misnomer here as many of these scripts are used by at least 20 million people. However their use is limited to a single country or language.
Nearly every Indian or Southeast Asian script letter means a simple syllable of some specific consonant and the “inherent vowel” A.
That inherent vowel may be changed into another vowel if by diacritical marks. These diacritical marks range from small dots above/below to letter-sized symbols to the side.
A letter with diacritical marks thus usually means any syllable of a single consonant and a single non-A vowel where the letter shows the consonant and the mark shows the vowel.
Additionally, some letters without diacrtical marks mean vowels without consonants. Consonants without vowels may be written by combining a letter with a “no vowel” diacritical mark. A syllable of multiple consonants and single vowel may be written by a ligature – an atypical combination of several letters representing those consonants and a diacritical mark representing vowel.
The father of all Indian/Southeast Asian scripts is the Brahmi script (used until ~3rd century A) thus sometimes all these scripts are called “Brahmic”. In these times there was no press and scripts evolved differently in each area.
In the south the letters became more rounded as they were commonly written on palm leafs which would have been torn by strait lines. Main scripts there are Sinhalese, Tamil, Malayalam, Tamil, Oriya, Telugu and Kannada, the final two separated only by the 19th century.
In the north the letters were more straight. Two most popular Indian scripts – Devanagari and Bengal script – both developed there. Other northern Indian scripts are Tibetan and Gurmukhi.
Pallava dynasty of the southern India brought southern Indian scripts to Southeast Asia through. There developed Thai, Lao, Khmer and Burmese scripts, all of them now prime scripts of independent nations. More Indian scripts were used in modern-day Philippines and Indonesia but the European colonists replaced those by the Latin script.