小 (xiǎo) means "small." Using it is as easy as talking about small things. Of course, 小 finds its way into some Chinese words, but the usage is logical, i.e. 小时 (xiǎoshí) means "(an) hour," 小心 (xiǎoxīn) means "to be careful" or "to take caution." 小孩 (xiǎohái), finally, means "child." Picking this word out should be easy for speakers of any level!