The distance or similarity between two languages can be objective or actual, i.e. discoverable by the tools and methods of linguists, or perceived by users of the languages. In this article two methods, the Levenshtein Distance (LD), which purports to measure the objective distance, and the Index of Perceived Similarity (IPS), which quantifies language users’ perceptions, are compared. The data are the quantitative results of a test measuring conscious perceptions of similarity between Estonian and Finnish inflectional morphology by Finnish and Estonian native speakers (‘Finns’ and ‘Estonians’) with no knowledge of and exposure to the other (‘target’) language. The results show that Finns see more similarity between Finnish and Estonian than Estonians do. Also the correlations between LD and the perception results of the Finns are statistically significant while the correlations between the LD and the IPS scores of the Estonians are not. Comments by test participants provide insights into the nature of the perceptions of similarity.
