It is an Italian word having the same meaning in English and in Spanish. In English it is spelled with two l's. as allegro. In Spanish it is spelled with only one l as in alegro. To determine the meaning:
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A Chihuahua will generally weigh between 2 and 6 pounds (.9 kg-2.7 kg) depending on body structure. One must remember that 6 lbs. maximum applies to show dogs and therefore pets that weigh a bit more than this guideline states is not necessarily a negative thing.