English has its own rules concerning how and when capital letters should be used. For example, the first letters of sentences, days, months and proper names have to be capitalised. It is considered to be a mistake and unacceptable if capitalisation is used wrongly. Furthermore, in English most Scottish family names use capitals in the middle of a word, for instance in McDonald, McClelland, McIntosh and McCarthy. In contrast, all letters in Thai are written in the same case no matter where they occur in words or sentences.