Five years ago I heightened my self-knowledge—abruptly. I had flown to Moscow to meet an executive in charge of Russia's railroads, and a press officer had offered a translator. I declined, believing that my conversational Russian would suffice.

How wrong I was. Seated at a conference table in the executive's capacious office, I was struck dumb by the streams of technical jargon zooming past my ears. It was swine flu season, and I couldn't tell if my forehead burned more from shame or genuine fever. I yearned to slide under that grand old table and curl up for a nap.

Faulty metacognition—our judgments of our knowledge and memories—had led me to overrate my language skills and perform poorly at a key moment. In “The Power of Reflection,” cognitive neuroscientist Stephen M. Fleming explains how metacognition underpins success in all walks of life. Fortunately, several techniques, such as meditation, can deepen self-knowledge.

A shared vocabulary is one aspect of successful communication, but raconteurs also swap subtle signals to intimate their thoughts. We focus on these enigmatic elements in this issue's special report on language. As linguists Mark Dingemanse and N. J. Enfield write in “Let's Talk,” conversations everywhere share a unique rhythm, which is why silences can be packed with social meaning.

The language you speak—whether it is native or foreign—adds further social nuance. People tend to think more rationally when speaking a language other than their mother tongue, for example. Psychologist Catherine L. Caldwell-Harris explores the quirks of the multilingual mind in “Kill One to Save Five? Mais Oui!

As Dingemanse and Enfield note, we spend most of our waking hours interacting with others. These exchanges are vital to well-being. In particular, socializing in groups can help people combat depression and avoid relapse. Psychologists Tegan Cruwys, S. Alexander Haslam (an advisory board member) and Genevieve A. Dingle describe this healing effect in “The New Group Therapy.

As for my botched reporting trip, the saving grace was that I had taped the whole affair. My benevolent mother helped me decipher the bureaucratese. Yet for the presence of the tape recorder, I have to grudgingly thank my metacognition.