The uncovering of linguistic strata, the stratigraphy, presupposes the etymologisation. The etymologic comment starts from the basic type and pursues a triple goal:<br>
- determination of the lexematic basis' language of origin;<br>
- explanation of the unity of all types which share the basic type. The regularities of historical phonetics and the semantic plausibility of the underlying concept relations are crucial for this.<br>
- reconstruction of borrowing paths if the basic type is spread in several language areas; as soon as the language of the etymon on the one hand and of the <a href="https://doi.org/10.5282/verba-alpina?urlappend=%3Fpage_id%3D493%26db%3D232%26single%3DM30">informant</a> on the other hand do not match, language contact is automatically established.