Personal language

A personal language, hermetic language, langue close, or heartlang is a language someone creates for personal use; the latter two terms emphasize that they try to become fluent in their language to use it in expressing their private thoughts in a way that natlangs or other conlangs aren't suitable for. Javant Biarujia's Taneraic is probably the most famous such hermetic language; he coined the term langue close by analogy with French maison close. Paul Burgess's mna Vanantha, which he also calls "Hermetic", was recently discussed at length in Sarah L. Higley's Hildegard of Bingen's Unknown Language. The term "heartlang" was coined by Rick Harrison.

While most conlangs produced by hobbyist conlangers could be considered "personal" in the sense that one's own enjoyment is the primary motive for creating them, a personal language is unique in a few respects. It is not associated with a conworld and has no fictional history or community of speakers. Neither is it intended for use in global communication. It also tends to receive much more care than a jokelang. With no fictional culture to reflect and no international audience of language learners to accommodate, a personal language more intimately reflects its creator's beliefs, thoughts, and attitudes.

The creator of a personal language may not make the language's grammar or vocabulary public, and may even take steps to prevent their accidental discovery, such as encrypting associated files or relying on pen and paper notes kept locked away. Such a jealously guarded language may be used to add an extra layer of obfuscation to a private diary, for example.