Spanish is a Romance language and the third most spoken language in the world. It is spoken as a first language by over 100 million people in Mexico and perhaps 20 million in the United States. Mexico is by far the world's most populous Spanish speaking nation. In Mexican Spanish, vowels tend to lose strength, while consonants are fully pronounced due to the influence of the Nahuatl language. Others have asserted that Mexican Spanish is leaning in the direction of a concomitant vowel reduction manifested in a greater stress timing likely caused by the geographic influence of American English. Mexican Spanish has also been influenced to a large extent by Mayan and Central American dialects. It is the predominant form used in the United States.