There is considerable debate within the field of syntax about the hierarchy of elements above the verb. Some linguists argue that the Tense Phrase (TP) dominates the Agreement Phrase (AP) (Pollock, 1989) while others argue the opposite (Belletti, 1990). æWhile data from a variety of languages is used to support both claims, no one has, as yet, explored the patterns of longitudinal first language acquisition. æThis type of evidence may shed light on the cognitive processes that generate these phrases, as core syntactic patterns are acquired in a universal order cross-linguistically, and if a pattern is seen in English, this may well help establish the most basic hierarchy of verbal elements. æIf we find that the TP is acquired before the AP, this would indicate that the AP dominates; if the converse, then the TP dominates. æWhile previous research shows an order of acquisition of verbal elements, tense and agreement are always treated similarly. The current study is more fine-grained, and attempts to track all levels of syntactic acquisition in the verb phrase (including agreement, tense, modality, perfective, etc,). ææææSarah and EveÍs (Brown 1973) longitudinal data in the CHILDES database (MacWhinney & Snow, 1985, 1990) were coded: 24,918 obligatory contexts were identified for Sarah, 19,034 for Eve. æUsing the threshold of 90% accurate usage in obligatory contexts, the preliminary results show that agreement is acquired before tense in SarahÍs data, indicating, crucially, that the Tense Phrase dominates the Agreement Phrase. EveÍs data are expected to mirror this result.