User Guide

Making OpenType Fonts
641
Language system
In practice, most or all of the features in a font will be registered under the
same set of language systems, and a particular feature's lookups will be
identical across the language systems that the feature is registered under.
The "languagesystem" statement takes advantage of this fact. It is the
simplest way to specify a language system in the feature file. One or more
such statements may be present in the feature file at global scope (i.e.
outside of the feature blocks or any other blocks) and before any of the
feature blocks:
languagesystem <script tag> <language tag>;
When these statements are present, then each feature that does not contain
an explicit "script" or "language" statement will be registered under every
language system specified by the "languagesystem" statement(s).
If no "languagesystem" statement is present, then the implementation will
behave exactly as though the following statement were present at the
beginning of the feature file:
languagesystem latn DFLT;