What does it mean to have knowledge of infinitives in English? First of all, it means that one properly forms the infinitive by using the word to followed by the basic form of a verb, as in to go, to study, or to procrastinate. In the first sentence below, the infinitive to study is properly formed; in the second and third sentences, the infinitive is not properly formed:
I need to study.
*I need study.
*I need to studied.
A second aspect of infinitive knowledge is reflected in the appropriate use of an infinitive clause as permitted after certain English verbs. Certain verbs, such as want, can be followed by an infinitive clause, as in the first sentence below, but cannot be followed by a clause beginning with a verb + ing (second sentence) or by a "that-clause" (third sentence):
The programmers want to finish the project.
*The programmers want finishing the project.
*The programmers want that they finish the project.
So knowledge of infinitives in this case means knowing that an infinitive clause (for example, to finish the project) can follow a main verb such as want. This broader knowledge of infinitives is really knowledge about words in general. In addition to knowing the meaning of a word, a native user of a language knows, subconsciously, which kinds of structures can combine with particular words and which kinds of structures cannot.
With respect to infinitive structures, a native user of English knows that some main verbs can be followed immediately by an infinitive clause as in the case of want and that some main verbs can be followed by both a noun phrase object and an infinitive clause. Some of the commonly used verbs that can be followed immediately by an infinitive clause are listed below:
The use of such verbs with infinitive clauses is illustrated in these sentences:
The manufacturing manager forgot to order replacement parts.
The hardware engineer refused to rewire the components.
Some common verbs that allow both an object and an infinitive complement include the following:
The use of such verbs with both an object and an infinitive clause is illustrated in the following sentence:
The software products manager allowed the programmer to alter the software.
It should be noted that some English verbs (for example, hope) cannot be followed by an object before the infinitive clause, that some verbs (for example, remind) must be followed by an object before the infinitive clause, and that some verbs (for example, want) can be followed by an object before the infinitive clause or just by the infinitive clause. The following pairs of sentences, some unacceptable (*), illustrate these facts:
The computer systems auditor hopes to investigate the problem.
*The computer systems auditor hopes the manager to investigate the problem.
*The customer reminded to send a new keyboard.
The customer reminded the service representative to send a new keyboard.
The systems analyst wants to complete the project.
The systems analyst wants the designer to complete the project.
Combining verbs appropriately with objects and infinitive clauses is what we are calling one aspect of an English user's "knowledge" of infinitives. However, it really reflects the user's broader knowledge of words in general and the properties associated with those words.
The third aspect of infinitive knowledge pertains to the interpretation of sentence structures containing infinitives. Specifically, it pertains to interpreting the logical subjects of infinitives, as discussed in the Grammatical Summary section of this module. Thus, knowledge of infinitives includes knowing that, in the first sentence below, the technician is understood as the logical subject (represented by the symbol "§") of the infinitive to repair whereas, in the second sentence, the engineer is understood as the logical subject of to repair.
The engineer asked the technician § to repair the computer.
The engineer asked the technician what § to repair.
In the first sentence, where the verb ask has a meaning similar to "request action," its object, the technician, is understood as the person who will do the repairing. But in the second sentence, where ask has a meaning similar to "request information," it is its subject the engineer that is understood as the person who will do the repairing.
The remainder of this section on Research Findings and Implications will focus on this third aspect of deaf students' knowledge of infinitives--the ability to interpret the logical subjects of infinitives in various sentence structures.