This paper revisits the key questions in current thinking in evolutionary linguistics, reviews the alleged stages during language evolution, and evaluates the mainstream hypotheses on language emergence, namely innatism and emergentism. We summarize both the supporting and opposing arguments for these hypotheses and evaluate two scenarios respectively following these hypotheses. As we will show, many of these arguments require an interdisciplinary collaboration between linguistics and other disciplines such as cognitive sciences, psychology, neuroscience, genetics, animal behaviors, and computer simulation, which illustrates the interdisciplinary nature of evolutionary linguistics and highlights the opportunities for future engagement of ou...