Since the invention of the printing press in the fifteenth century, the western European languages have become increasingly static. In Spain, the relatively early political unification of the country, the expulsion of non-Spanish linguistic groups and the appearance of Nebrija's grammar all contributed to the standardization of the language on the peninsula. The maturity of the language implanted by the sixteenth-century conquistadores on the shores of America helped it to survive in spite of the heavy pressures exerted by the languages of the many highly developed Indian civilizations. In the twentieth century, because of newspapers, radios, and other modern means of communication, phonetic and morphological changes are indeed rare. Nonetheless, languages are continuing to grow in vocabulary. The sports world, and particularly baseball, which has so captured the fancy of the public in Mexico, Cuba, Puerto Rico, and Venezuela, affords an excellent opportunity to examine the processes involved in the expansion of Spanish. The following study is limited to Mexican baseball terminology and is based on a baseball dictionary that I have compiled from Mexico City's three leading daily newspapers, El universal, Novedades, and Excelsior, August 8-17, 1953. Just as Spanish has taken some of its mathematical and architectural words from Arabic, some musical words from Italian and some courtly and gastronomic words from French, it is now taking its baseball words from English. The growth of the Spanish baseball vocabulary is being achieved generally in three different ways: a word may be taken bodily from English and written in English; the same word may be transcribed phonetically in Spanish; or it may be translated, literally or figuratively. Sometimes, the phonetic transcription is incomplete, and may often be limited to the placing of an accent on the stressed vowel of the English word.