This paper unsystematically reviewed the journal publications written in English in the period from 2010 to 2020 on the topic of early infancy language acquisition. The review was through two aspects: language comprehension, and language production. Additionally, this paper also reviewed several frequently used and new research methods and tools. For early infancy language comprehension, empirical studies found evidences on infants’ comprehension of words’ meaning through sounds, especially the comprehension of nouns, the latter was proven to have relevance with nouns’ familiarity and cross-word relations in the nouns. Besides, empirical studies found evidences on infants’ distinguishment between concrete words and abstract concepts. An important factor to influence infancy language comprehension is the social environment that the baby was exposed to, mainly the mother’s speech and her daily life routine (for example, her work). For early infancy language production, empirical studies found evidences on infants’ ability to associate similar sounds with different objects, and measurement for infants’ language outputs were brought forward in another empirical study. Empirical studies also found infants’ language outputs match to words and objects from the environment. Lastly, this paper reviewed the most frequently used technical methods: fMRI and fNIRS technology for investigating neural mechanisms of infancy language processing. There are other new research methods, include large-sample database analysis and quantitative modeling, corpus analysis, language inputs sampling, language model for infancy language acquisition.