After 400,000 years ago and the second interglacial period, unlike the speciation 6 million ya, was different and mild and caused the trend in intra-cranial volume expansion, not via microcephalin in the Neanderthals, who interbred with the EH with FOXP2 but the (fetal and post-birth) gene expression was different and they had no vocal learning. Interbreeding was possible due to similar appearances, as within a clade, but difference in speech capacities became more pronounced over 300K years to set the Neanderthals apart and lost out as observational learning was insufficient, while it forced them to inbreeding, leaving a small percentage of their genes in modern humans through earlier interbreeding, before 40K years. Speech capacity gives vocal learning for sophisticated culture and technology developments that began to accelerate in modern humans.