• Sublime Text 3 for writing.
• Audacity to record myself.
• Photo Booth (Mac) as a webcam feed to, literally, watch my lips.
• Wiktionary, foremost en.wiktionary.org, but also local editions (ru.wiktionary.org, hu.wiktionary.org, etc.)
• Alfred to create shortcuts to online dictionaries and other reference sites
• Alinof Timer (Mac) to work in chunks of X minutes
• Lang-8.com to receive free corrections on your writing. Unfortunately, they're closed to new registrations, but you can use HiNative instead.