More intelligent AAC systems of the future will be able to take advantage of an understanding of what meaning the user intends to convey in order to facilitate the communication of the user in ways that present systems cannot. These more intelligent AAC systems are distinguished by having a deeper understanding of the expression the user wishes to convey. They must have some understanding of what is actually meant by the input from the user and the language generated. Techniques from NLP can empower a computer system to understand abbreviated input, track previous expressions, recognize communicative goals, and disambiguate expressions with the help of specified world knowledge. The goal is to have a computer system that can help a user communicate with insight similar to that of a human aid.
Several elements come into play here.
The context could tell us whether this is a command or a question. Exxon is a company that can only be purchased in part, via stock, is important. Knowing that stocks are bought with money is also important. Therefore, it may be necessary for a system to require that metaphorical expressions be excluded. Otherwise they will be unable to behave adequately, and would fail their task.