The Meithei language is the predominant language of the eastern Indian state of Manipur as well as parts of Myanmar (Burma). From the 11th century onward, it was written with a distinctive syllabic alphabet called Meithei Mayek. Despite its close proximity to Indic scripts such as Bengali, Meithei Mayek actually shares more commonalities with Tibetan, which you will see below.
The following is the basic letters of Meithei Mayek. As it is a syllabic alphabet, each letter carries an inherent vowel, which is /ə/ in Meithei's case.
In order to represent a vowel other than /ə/, Meithei Mayek follows other Brahmi-derived scripts by adding diacritical marks around the letter to modify the inherent vowel. One notable difference with Indic scripts but similarity with Tibetan is how vowels at the beginning of words are represented. In Indic scripts, there is a different letter for each word-initial vowel. However, in Meithei, there is a single letter to denote word-initial vowel, and diacritical marks are added to it to change it into another vowel.
Note that there are seemingly two letters for /i/ and also two for /u/. In reality, they represent the sounds /i/ and /u/ in two different tones. Meithei is a Tibeto-Burman language and has tones typical of many languages in that family. However, the representation of tones in the Meithei script is not complete. Tones are denoted only in a few cases (such as this), and often disambiguation of which tone is intended can only be achieved by context of the sentence.
The Meithei Mayek ceased to be the writing system for the Meithei language in the 18th century CE. Instead, the Bengali script was adopted as Meithei's writing system.