One of the most notoriously tricky aspects of learning the English language for speakers of other languages is getting to grips with phrasal verbs. Many native English speakers may not even recognise the term "phrasal verb" in the first place and, even if they do, they may find themselves rather tongue-tied when attempting to break down the semantic patterns behind many such verbs. The first point to note is that while a certain proportion of phrasal verbs are found in formal contexts, a far wider variety are used in informal contexts.
Phrasal verbs with 'out' that have a clear physical connotation (such as 'go out', 'eat out' or 'get out') obviously do not pose too much difficulty for learners. However, the majority of phrasal verbs are not so easy to decipher as they possess a figurative dimension. When trying to remember the meanings of the variety of phrasal verbs using 'out' that deal with human relations, it may be useful to think of similar-sounding phrases that you have already learnt and whose meanings are usually related in some way. For example, if you have trouble remembering the meaning of the phrase 'to fall out with someone', think of it as an expression that has more or less the opposite connotation of 'to fall in love with someone'!
In the case of phrasal verbs ending with 'out' that are subject to direct objects in a sentence (i.e. nouns or pronouns), where 'out' does not signify the idea of a physical 'outside' (literally or figuratively), the meaning that is inferred is often that of moving towards achieving a goal or completing a task (at least where human beings are involved in the action). Consider the following common examples:
(1) To carry out a task
(2) To fill out a form
(3) To work out a solution
(4) To hammer out a deal
(5) To carve out a livelihood
Each of these phrasal verbs emphasises the importance of procedure and/or perseverance in bringing a task to its concluding stages. Examples (3), (4) and (5) represent informal speech and it is these varieties of phrasal verbs which, in many cases, are very descriptive, since they have the ability to instil a deeper understanding of a given situation on the part of a reader or listener through the information that is made implicit by them. The noun or the verb that precedes the word 'out' tends to originate in a physical context (such as hammering a nail in a wall or carving out one's initials on a tree trunk). Meaning is then constructed within the minds of the readers or listeners through these metaphorical allusions.
Perhaps the common colloquial phrase 'to go all out' best exemplifies the link between the word 'out' in many phrasal verbs and the notion of processes or intense efforts that lead to desirable conclusions. The following sentence, which illustrates how determined individuals spare no effort in order to achieve their goals, should serve as a good model:
The football team knew they would have to go all out with their training and tactical preparation over the following season in order to win the league cup.
There are, of course, other examples of phrasal verbs using 'out' that imply a sense of conclusion and finality which describe situations that do not directly refer to human action. If you read a text based on the topic of maths or statistics, for instance, you may come across the expression 'to average out', which would refer to the general significance of a set of unequal values by calculating the average value1. Similarly, 'to cancel out', in an analytical sense, implies that a particular variable (such as cost) has an equal weighting to another variable (such as perceived benefit) and therefore there is no longer a positive effect but a neutral one.
Where direct objects are not directly connected to the phrasal verb, the word 'out' generally does not imply the notion of process, but merely acts as a support to the verb that precedes it, completing and augmenting its meaning within a defined context. Here are some common examples taken from colloquial usage: "You're creeping me out!"; "She freaked out when she saw the damage that was done"; "He couldn't believe that he had been caught out".
English phrasal verbs, particularly colloquial ones, cannot always be categorised in perfectly logical ways as languages do not evolve and develop over time in the same way as species of plants or animals do! However, studying general rules, such as those mentioned above, can certainly be beneficial when, as a learner, you are trying to grasp the basic patterns that such verbs follow and the contexts in which they appear.