Spanish missionaries started to write in the language during the early 18th century. As a result of the eventual 300-year Spanish colonial period, Cebuano contains many words of Spanish origin. While there is evidence of a pre-Spanish writing system for the language, its use appears to have been sporadic. Spaniards recorded the Visayan script which was called "Kudlit-kabadlit" by the natives. The colonists erroneously called the ancient Filipino script "Tagalog letters", regardless of the language for which it was used. This script died out by the 17th century as it was gradually supplanted by the Latin script. The language was heavily influenced by the Spanish language during the period of colonialism from 1565 to 1898. With the arrival of Spanish colonists, for example, a Latin-based writing system was introduced alongside a number of Spanish loanwords. Due to the influence of the Spanish language, the number of vowel sounds also increased from three to five. Below is the vowel system of Cebuano with their corresponding letter representation in angular brackets:  Sometimes, may also be pronounced as the open-mid back unrounded vowel (as in English "gut"); or as the near-close near-front unrounded vowel (as in English "bit"); and or as the open-mid back rounded vowel (as in English "thought") or the near-close near-back rounded vowel (as in English "hook"). During the precolonial and Spanish period, Cebuano had only three vowel phonemes: , and . This was later expanded to five vowels with the introduction of Spanish. As a consequence, the vowels or , as well as or , are still mostly allophones. They can be freely switched with each other without losing their meaning (free variation); though it may sound strange to a native listener, depending on their dialect. The vowel has no variations, though it can be pronounced subtly differently, as either or (and very rarely as immediately after the consonant ). Loanwords, however, are usually more conservative in their orthography and pronunciation (e.g. "dyip", "jeepney" from English "jeep", will never be written or spoken as "dyep"). For Cebuano consonants, all the stops are unaspirated. The velar nasal occurs in all positions, including at the beginning of a word (e.g. "ngano", "why"). The glottal stop is most commonly encountered in between two vowels, but can also appear in all positions.