Modal particles, discourse markers, 
and adverbs with lt-suffix in Estonian

This paper discusses a series of invariable Estonian adverbs with an lt-suffix and attempts to account for them within the framework of grammaticalization. This study investigates the functions of the forms loomulikult ‘naturally; of course’, ilmselt ‘visibly; apparently’, tegelikult ‘in reality; actually’, and lihtsalt ‘simply; just’ from the 1890s to 2000s. Excerpts from Estonian fiction and newspaper texts demonstrate the use of identical word forms as autosemantic items (adverbs) as well as synsemantic items (pragmatic markers). The paper suggests that the category of pragmatic markers can be further divided into two subcategories, modal particles and discourse markers. Several criteria that support the classification into subcategories will be outlined.