La writes the lateral liquid, the sound spelled l in English, and it is the fifteenth letter of the alphabet. Like the bilabial nasal before it, it is a plainly written native consonant with no harmony alternation and no shared shape to resolve, which makes it one of the anchors a learner can rely on while working out the more ambiguous letters around it.
Unicode encodes it at U+182F. The lateral is also the letter most often held up as an example of Mongolian calligraphy, because its long descending stroke gives a calligrapher the kind of extended line that shows the control of the brush. Traditional Mongolian calligraphy is a living art with its own vocabulary of stroke names, and because the script is written down a continuous spine, a calligraphic word is a single sustained gesture rather than an assembly of separate marks.
The comparison usually drawn is with Arabic rather than with Chinese: both are cursive alphabets in which the joining is the point, both developed elaborate hands for religious and chancery use, and in both the aesthetic problem is how to distribute weight along a line that never lifts. The Mongolian solution runs downward instead of across, which changes the balance of the page entirely.