Ambiguity in some syntactic structures of the same language has always posed problems to the human translator and to machine translation. These problems become more complex for the Machine Translation of genetically unrelated languages such as Arabic, English and French. Arabic Lexical ambiguity in Natural Language Processing (NLP) also poses problems when the semantic fields of Arabic words differ from those of English for instance. This often occurs when two or more words from Arabic equate to a single word in English. Semantic gaps between the two languages are also a source of ambiguity in Natural Language Processing. We shall deal with some cases of ambiguity in machine translation from Arabic to English and French and vice versa. The questions addressed in this paper relate to segmentation, determination / non-determination, coordination and the issue of the word as a meaningful and functional unit. Some aspects of the segmentation of constituents into grammatical categories and their comparison with structures of Arabic English and French are addressed in this paper.