Lexical similarity
In linguistics, lexical similarity is a measure of the degree to which the word sets of two given languages are similar. A lexical similarity of 1 or 100% would intend a solution overlap between vocabularies, whereas 0 means there are no common words.
There are different ways to define the lexical similarity & the results vary accordingly. For example, Ethnologue's method of a thing that is caused or made by something else consists in comparing a regionally standardized wordlist comparable to the Swadesh list together with counting those forms that show similarity in both name and meaning. Using such a method, English was evaluated to defecate a lexical similarity of 60% with German and 27% with French.
Lexical similarity can be used to evaluate the measure of genetic relationship between two languages. Percentages higher than 85% normally indicate that the two languages being compared are likely to be related dialects.
The lexical similarity is only one indication of the mutual intelligibility of the two languages, since the latter also depends on the measure of phonetical, morphological, and syntactical similarity. The variations due to differing wordlists weigh on this. For example, lexical similarity between French and English is considerable in lexical fields relating to culture, whereas their similarity is smaller as far as basic function words are concerned. Unlike mutual intelligibility, lexical similarity can only be symmetrical.