You will need to send the command TWITCHCLIENT 3 to opt-in to receive that information. Once subscribed before more every message a user sends there will be an accompanying group of messages from jtv with the list of emote sets the user has access to.
TWITCHCLIENT 3
:jtv!jtv@jtv.tmi.twitch.tv PRIVMSG #channelname :EMOTESET nickname2 [27,1690,84,2132,42,240]
:nickname2!nickname2@nickname2.tmi.twitch.tv PRIVMSG #channelname :message was sent
You can than match that up with the emoticon_set in /chat/emoticons.