Thus the specifically sexual meaning of the term has passed into common usage to include the sexual behavior of heterosexual persons, as well. The protective barrier once provided by the term 'cruising' as a 'code word' has therefore largely broken down and, arguably, become increasingly irrelevant. In the latter half of the twentieth century, decriminalization of homosexual behaviour increasingly became the norm in English-speaking countries. This served (and in some contexts, still serves) as a protective sociolinguistic mechanism for gay men to recognize each other, and avoid being recognized by those who may wish to do them harm in broader societies noted for their homophobia. In a specifically sexual context, the term 'cruising' originally emerged as an argot 'code word' in gay slang, by which those 'in the know' would understand the speaker's unstated sexual intent, whereas most heterosexuals, on hearing the same word in the same context, would normally misread the speaker's intended meaning in the word's more common nonsexual sense. According to historian and author Tim Blanning, the term cruising originates from the Dutch equivalent kruisen.