The vowels can be long or short in Finnish orthography which can take place in a stressed or unstressed syllable, meaning when emphasis is caused such as during an accent.
In Finnish, both vowels and consonants may be either short or long. Either a long or short vowel may occur in a stressed as well as unstressed syllable. In linguistics, and particularly phonology, stress or accent is relative emphasis or prominence given to a certain syllable in a word, or to a certain word in a phrase or sentence. That emphasis is typically caused by such properties as increased loudness and vowel length, full articulation of the vowel, and changes in tone. The terms stress and accent are often used synonymously in that context but are sometimes distinguished. 
