Tier 2 words as shown in this link are High-frequency words used by mature language learners across many subjects or content areas. These make you sound more fluent. You likely already have ways to express the same ideas or concepts, but these are more complex words that you may not be exposing yourself to enough.
*However, please note that these are words that are usually taught under the instruction of a teacher because he or she will know whether you have enough words to express the same ideas in a more basic way. If you cannot express the same idea in a more basic way, then these words are too advanced for you*.
Tier Two words Students' likely expressions that they already use correctly
merchant salesperson or clerk
Here is a link to a site that can help you start learning more words. We provide these lists in American schools starting at a very young age. So start at the lowest level and work your way up. Remember if you cannot express these words using more basic words, then you have gone too far in the list or grade level.
Email or sign up for a lesson if you want or need more help with this. Good luck!