Download a portion of a playlist:
youtube-dl --playlist-start 2 --playlist-end 8 https://www.youtube.com/playlist?list=…
Download a video with subtitles:
youtube-dl --write-sub --write-auto-sub https://www.youtube.com/playlist?list=…
write-sub
downloads the manually created subtitleswrite-auto-sub
downloads the auto-generated subtitles