The TOEIC (Test of English for International Communication) test measures the English proficiency of people working in internationai business or pianning to use English to communicate with others. Although the test does not specifically test specialized vocabulary, the items on the exam are in specialized contexts.
Vocabulary is something you can never have enough of. Even the same words over time develop new or additional meanings. In the TOEIC test, you can get answers wrong because your vocabulary isnt broad enough. It may not necessarily be a hard word or phrase either, it might be an alternate meaning youre not aware of. So the more vocabulary you know the better. A large vocabulary range is something you can use for life, its knowledge not limited to just being useful to get a high score.
But you should definitely widen your vocabulary range and get a feel for what to expect on a TOEIC test. Online you can find lots of free material to help you with your vocabulary from ESL/EFL websites as well as ones specifically for TOEIC. Searching with TOEIC vocabulary will bring up lots of results. An example is this application.
This Application will provide you with a basis to understand these specialized contexts that are often used on the TOEIC test.
Each topic covers a particular context that has appeared on the TOEIC test. The new words taught in each chapter are not specialized words. These words are more what is called general vocabulary. They can be used in many contexts.