Previous research (e.g. Belz & Thorne, 2006; Ware & O’Dowd, 2008) has discovered that language learning can be afforded through intercultural telecollaboration. From a sociocultural theoretical perspective, the current study investigated the language development outcomes and process in a 10-week Sino-American telecollaborative project involving 10 college-level American learners of Mandarin Chinese and their respective native Chinese partner from China. The findings show that American learners’ production quantity in Mandarin Chinese increased steadily throughout the project whereas the quality of their production didn’t improve as rapidly. They also self-reported gains in age-appropriate cultural information, reading ability, and expanded vocabulary. The analysis shows the gains can be attributed to the scaffolding conditions (van Lier, 1996, 2004) that focused on friendship building and idea sharing in Mandarin Chinese and were specifically manifested in the operation of intersubjectivity, contingent help and handover by both American learners and their Chinese partners throughout the project. Possible underlying reasons for the unbalanced focus on form versus on meaning in the project were discussed. Based on the findings, pedagogical suggestions are provided to enhance the learning conduciveness of email-based intercultural telecollaborative projects, particularly those involving participants from oriental cultures.