| English | eng-000 |
| linguistic theory | |
| Deutsch | deu-000 | Sprachtheorie |
| eesti | ekk-000 | keeleteooria |
| eesti | ekk-000 | lingvistiline teooria |
| English | eng-000 | theory of language |
| français | fra-000 | theorie du langage |
| français | fra-000 | theorie linguistique |
| hrvatski | hrv-000 | lingvistička teorija |
| russkij | rus-001 | lingwistitschjeskaja tjeorija |
| español | spa-000 | teorías sobre el lenguaje |