Tagalog is the most important of the many tongues and dialects of the Philippines on account of its being widely understood, and the most developed by contact with foreign idioms. Spoken by over ten million of an energetic race in the islands occupying the capital city of Manila, eight provinces surrounding the metropolis, and a number of outlying islands and districts beyond these limits, it is also generally understood by many far beyond its own territory, especially in seaport towns throughout the archipelago.The language seems to be divided into a northern and a southern dialect, the former being spoken in Bulacan, Bataan, Nueva Ecija, Rizal, and parts of Tarlac, and the latter occupying La Laguna, Batangas, Cavite, Tayabas, Marinduque, the coast of Mindoro and part of the Camarines Norte and Camarines Sur. Dialect differences though can only be distinguished by local mannerisms in pronunciation but very seldom in meaning. Philologically, Tagalog belongs to the Malayan branch of the great Malayo-Polynesian linguistic family, which extends from Hawaii to Madagascar and from Formosa to Easter Island west of Chile, including New Zealand, Tonga, and Samoa, as well as Borneo, Celebes, Java, Sumatra, the Malay Peninsula, and the Philippines from east to west, a distance of 180 degrees, or half the circumference of the earth.

Tagalog, together with other civilized tongues of the Philippines, such as Visayan, Pampango, Ilocano and Bicol, has preserved the verbal system better than any other. The basis for the comparative study of the family must be taken from the Philippine tongues and not from the more cultivated Malay, Kawi, or modern Javanese, all three of which have been profoundly affected by Sanskrit and to a lesser degree Arabic, something as English has been affected by Latin and French elements. The number of roots or primitive-idea words in Tagalog seems to be about 17, 000 there being 16, 842 words in the Noceda and Sanlucar dictionary of 1832. Of these some 284 are derived from the Sanskrit, and are evidently borrowed through the Malay. Many of these are names for the things unknown to the primitive Malayan peoples, but others are abstracts and various words, some of which would seem to have supplanted a primitive Malayan word. Thus in may cases Americans and Tagalogs use words in their own languages which are from the same remote source in India, and coming aroung the earth east and west to meet again in the Philippines.

The Japanese language seems to have furnished no words to the Tagalog although many Japanese came to the Islands during the seventeenth century owing to the expulsion of Japanese converts to Catholicism, who found a refuge in Manila and the adjoining provinces, mainly in Pampanga. Notwithstanding a comparatively close contact with the Chinese for several centuries and certainly antedating the Spanish conquest by many hundred years, the Chinese element in Tagalog seems limited to a few commercial terms, some household implements, and a few miscellaneous words. The Arabic words in Tagalog, which are hardly more than a dozen in number, evidently came in with the Mohammedan religion, and upon the extinction of that faith around the mouth of the Pasig, all but a few words fell into disuse. Spanish, as a matter of course, has contributed a great number of words to Tagalog, many of which have been thoroughly naturalized. They are mainly religious, governmental, social, legal and abstract terms, including terms for foreign articles and luxuries. Some names for Mexican articles are not Spanish, but Nahuatl or Aztec, owing to the intimate connection between Mexico and the Philippines for more than two centuries. English has as yet given but a few words to Tagalog.

English words which have no exact native or Spanish equivalent are taken into the language bodily, while many others are still quoted.The construction of Tagalog does not seem to have been influences by any of the foregoing languages but has retained its Malayan structure. As has been already mentioned, there are some 17,000 roots in the Tagalog language, many of which are nouns, pronouns, adverbs, and prepositions. Verbs are generally formed by the use of certain particles (affixes) of which there are more than twenty. Together with the noun and the adjectives forming particles, of which there are several, the possible number of intelligible Tagalog words can not be far from 50,000 to 60,000; quite sufficient to express any non-technical ideas of any language whatsoever. Yet, with all these there are some curious facts about the language and its vocabulary. Many general terms can not be expressed in one word, but the modifications of a general act have many words to express them, sometimes far more than exist in English and Spanish.

In addition to such particularizing words, there are also many synonyms or words meaning the same thing in Tagalog, many of which are local or provincial or not heard in the same locality. In Tagalog, there are twelve (12) names for the coconut, including its different varieties and conditions for the maturity and preparation for use. The verb to carry, with its variations has some eighty words to express all combinations in Tagalog. It should be borne in mind that Tagalog is not constructed on English or Spanish lines, either in grammar or syntax. The universal tendency upon using a new language is to translate one's own language word for word, or phrase for phrase, into the foreign one. The native may understand but the result is not elegant.
No language can be learned entirely from books, and to supplement the special needs of each person, constant practice in speaking with educated or intelligent Tagalogs is necessary.

Even with a considerable vocabulary, the American or any other foreigner, will find difficulty in conveying just what he wants to say in Tagalog unless he masters the idioms and peculiarities of the language. This will not be a very easy task, but once mastered, the key is held to all the Philippine languages, and it might be said, to all the Malayan languages of the East Indies.