The author surveys the problems of bilingual and bicultural tensions in Canada, Cyprus, Switzerland, Italy, Asia, Africa, and the Americas. Classification of bilingualism is proposed to show: two official languages; semi-official and official languages; unofficial and official languages; official and national languages. Examples of national language patterns are given showing the number of official languages and types of unilingual, bilingual, and multilingual speakers. "Cultural accents" result from interference of conflicting cultural patterns, and bilingualism and biculturalism do not necessarily coincide. In examining the correlation between phonology, morphology, or syntax and biculturalism, linguists will need to work with the other social sciences. "Cultures in contact" is a more comprehensive term than "acculturation." Such cultures can be classified as "enclavic," symbiotic," and "mixed." The author suggests a distinction between individual and community contacts, diachronic and synchronic approaches, and presents a formula, similar to a linguistic formula, for comparison of cultures in contact. (MK)