General Rules for Language (required) for Entire Journal Titles Vancouver Style

Give the language of publication if not English.

Capitalize the language name.

Follow the language name with a period.

Según:

Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers [Internet]. 2nd edition. Chapter 1: Journals

Related:

General Rules for Language (required) for Entire Journal Titles Vancouver Style

Specific Rules for Language (required) for Entire Journal Titles Vancouver Style: Journals appearing in more than one language

Examples of Language (required) for Entire Journal Titles Vancouver Style