The article reports the development of the Structural Analysis of Written Language (SAWL), an instrument designed for use by classroom teachers in objectively documenting the ability of children to write in English. The SAWL allows teachers to use T-unit analysis to quantitatively assess language improvement regardless of whether the student writes perfect English, flawed English, and/or generates "wordstrings" with minimal English structure. The SAWL introduces two new indexes of linguistic maturity, morphemes per T-unit (MTU) and the word efficiency ratio (WER). The SAWL also allows teachers to (a) objectively compare a child's written composition with printed material and (b) make a seamless comparison of a student's written English across his or her academic life using the same indexes of measurement. (Contains 3 figures and 4 tables.)