Indeed, while there is a logic to Finnish's system of consonant gradation (changes to the consonants of words in different noun and verb forms), it is only comp

Indeed, while there is a logic to Finnish's system of consonant gradation (changes to the consonants of words in different noun and verb forms), it is only completely graspable by those with some knowledge of historical linguistics. Ordinary learners have to simply memorize many things by rote. This is why Harjoitus tekee mestarin, a popular workbook series for foreign learners of Finnish, provides hundreds of pages of exercises to help students memorize the different noun declensions and verb conjugations, and it is not an easy task. Then, after you have learned the complicated written language, learning the actual spoken Finnish used in everyday life involves learning even more such exceptions. (Finland has diglossia not too different from, say, what reigned in Greece until the 1970s).