This commonly comes up due to the standard practice (in English and many other languages) of automatically capitalizing the first word of a sentence.
Truecasing is unnecessary in languages whose scripts do not have a distinction between uppercase and lowercase letters.
This includes all languages not written in the Latin, Greek, Cyrillic or Armenian alphabets, such as Korean, Japanese, Chinese, Thai, Hebrew, Arabic, Hindi, and Georgian.
Truecasing aids in other NLP tasks, such as named entity recognition (NER), automatic content extraction (ACE), and machine translation.
Some translation systems use statistical machine learning techniques, which could make use of the information contained in capitalization to increase accuracy.