They used a system that is termed as an "abugida", or an alphasyllabary. It was similar to the Tagalog and Pangasinan scripts, where each character represented a consonant-vowel, or CV, sequence. The Ilocano version, however, was the first to designate coda consonants with a diacritic mark – a cross or virama – shown in the "Doctrina Cristiana" of 1621, one of the earliest surviving Ilokano publications. Before the addition of the virama, writers had no way to designate coda consonants. The reader, on the other hand, had to guess whether the vowel was read or not, due to this vowels "e" and "i" are interchangeable and letters "o" and "u", for instance "tendera" and "tindira" (shop-assistant). In recent times, there have been two systems in use: The "Spanish" system and the "Tagalog" system. In the "Spanish" system words of Spanish origin kept their spellings. Native words, on the other hand, conformed to the Spanish rules of spelling. Most older generation of Ilocanos use the "Spanish" system. In the system based on that of Tagalog there is more of a phoneme-to-letter correspondence, and better reflects the actual pronunciation of the word. The letters "ng" constitute a digraph and counts as a single letter, following "n" in alphabetization. As a result, numo "humility" appears before ngalngal "to chew" in newer dictionaries. Words of foreign origin, most notably those from Spanish, need to be changed in spelling to better reflect Ilocano phonology. Words of English origin may or may not conform to this orthography. A prime example using this system is the weekly magazine "Bannawag". The following are two versions of the Lord's Prayer. The one on the left is written using the Spanish-based orthography, while the one on the right uses the Tagalog-based system. With the implementation by the Spanish of the Bilingual Education System of 1897, Ilocano, together with the other seven major languages (those that have at least a million speakers), was allowed to be used as a medium of instruction until the second grade. It is recognized by the Commission on the Filipino Language as one of the major languages of the Philippines. Constitutionally, Ilocano is an auxiliary official language in the regions where it is spoken and serves as auxiliary media of instruction therein.