If you are arriving from a country with a Cape Verde embassy, you will be required to purchase a Visa in advance. Otherwise a visa can be purchased on arrival.
The Cape Verde Bureau Cape Verde Consul in Liverpool, England provides travel visas for travellers from the UK and Ireland.
Cape Verde has an embassy in Lisbon, Portugal. (http://www.embcv.pt/lista...)
Cape Verde has an embassy in Brussels, Belgium.
Cape Verde has an embassy in Geneva, Switzerland.
Cape Verde has a consulate in Rotterdam (http://www.conscv.nl/serv...), The Netherlands.
Cape Verde has an embassy in Washington, D.C., USA
Cape Verde has a consulate in Moscow, Russia. (http://cv-consul.ru/en_vi...)
Cape Verde has an embassy in BrasÃlia, Brazil. (http://www.embcv.org.br/p...)
Cape Verde has a consulate in Vienna, Austria. (http://www.konsulat-kapve...)
The official language is Portuguese, used in all official publications and announcements as well as in business, media and schools, but the local language is Cape Verdean Creole Kriolu kabuverdianu, a Portuguese-based creole language with 90-95% of the words from Portuguese and the rest mainly from West African languages. It is divided into 9 dialects spoken on various parts of the country. Even though Kriolu is comprehensible to a skilled Portuguese-speaker almost all people can also speak Portuguese as a second language. French Creole is not the same as Cape Verdian creole, and a considerable number also speak English; basically, Kriolu is your first option, Portuguese second, English third.
It is a good idea to know some Kriolu or at least Portuguese, since even though young urban people are often quite proficient in English, this does not apply to old and rural people, and even those who can speak English will highly appreciate any attempt you do to speak Kriolu or Portuguese.