^Indeed, that sounds dumb. Common language for scientific issues is hardly the main barrier, cause it is a field with already hugely common symbols, methods and manner it is being taught. Unless he means "sciences" like sociology etc, his claim is just a false note, coming from possibly a broken piano.
In physics, chemistry, also math (i know it isn't termed as science, sometimes, whatever) the issue is very unlikely to be language of communication. While knowing more languages can have up to a considerable effect on overall way of thinking, having to use one language to publish scientific stuff seems to have next to zero negatives.