This feature would highlight words that have corresponding emojis. For example, you type car and it becomes highlighted. Tapping on the highlighted word would bring up a little text bubble above the word showing all the related emojis for that word (in this case, all the different car emojis) Tap the emoji you want to use it. Simple, fast and easy. I just switched from Verizon Messages+ which has this feature and it's amazing and very very useful and makes using emojis SO much quicker. I honestly miss it a lot and hope that Textra will implement this feature in their next update.