python

Alex Martelli's Google Developers Day talk on classic design patterns (creational, structural and behavioral) and how they appear in Python. He stresses that patterns must be studied in the context of the implementing language.

Joshua Bloch's Google Tech Talk on how to design good APIs and why it matters, with concrete principles and examples. It treats every programmer as an occasional API designer.

Robert Martin's RailsConf 2009 talk looks at why Smalltalk lost out despite its technical strengths. He draws lessons about language communities and arrogance that he argues could hurt Ruby too.

Cliff Click of Azul Systems gives a Google Tech Talk on running Java business applications on a machine with about a thousand cores. He covers hardware and software codesign, including garbage collection hardware and the JIT.

Peter Norvig's 2007 Google talk on theorizing from data, covering what huge datasets can do for language understanding, translation, information extraction and inference. It argues that more data often beats cleverer models.