This is a descriptive research on the difficulties of Filipino high school students in translating algebraic word problems into mathematical equations. This research is composed of three parts: (1) development of an 11-page "Filipinized" questionnaire; (2) analysis of the mathematical thinking processes of the respondents based on the answers to the questionnaire; and (3) identification of the alternative conceptions or errors of the students in translating word problems which lead to incorrect or misconceived answers. Through the instrument and students' answers analysis, this research categorizes the assimilation errors made by high school respondents as LBE (language-based errors), OIE (operational-influenced errors), ATE (algebraic translation errors), and RSE (relational-symbol errors). This research recommends a review of the construction of word problems in terms of its realness and logic to match students' mathematical background. (Contains 1 table and 2 figures.)