Using a psycholinguistic and a holistic bilingual perspective, this study examined the writing conceptualization progressions in Spanish and English of 16 simultaneous bilinguals from preschool through kindergarten. The children were enrolled in a bilingual early childhood program where literacy instruction was primarily in Spanish. We adapted a clinical method used in previous studies to examine the evolution of their biliterate writing, paying particular attention to whether children pass through a syllabic period as they begin to establish sound-letter relationships. Findings indicate that children’s writing in Spanish and English developed in parallel without one language lagging too far behind the other, despite not receiving formal literacy instruction in English. The simultaneous bilingual children in our sample did not seem to begin establishing sound-symbol correspondence through the construction of the syllabic hypothesis. Instead, some children demonstrated their emergent understanding of sound-letter relationships by representing the first sound of a word. The majority of the children, however, seemed to have discovered the relationship between sounds and letters by attending to both syllables and sounds within a word. Both the essence of being simultaneous bilingual and the literacy instructional methods teachers used may have prevented children from constructing the syllabic hypothesis. (author abstract)