I. Read the following text and answer the questions below:
In order to study how learner acquire a second language, a clear, operational definition of what is meant by the term ‘acquisition’ is needed. Unfortunately, researchers have been unable to agree on such a definition. ‘Acquisition’ can mean several things. First, some researchers (for example, Krashen 1981) distinguish between ‘acquisition’ and ‘learning’. The former refers to the subconscious process of ‘picking up’ a language through exposure and the latter to the conscious process of studying it . According to this view, it is possible for learners to ‘acquire’ or to ‘learn’ rules independently and at separate times. Although such a distinction can have a strong face validity –particularly for teachers- it is problematic, not least because of the difficulty of demonstrating whether the knowledge learners possess is of the ‘acquired’ or ‘learnt’ kind. That is why many books use the terms ‘acquisition ‘ and ‘learning’ interchangeably. Second, researchers disagree about what kind of performance they think provides the best evidence of acquisition. We have already noted that some researchers work with production data, some study learners’ intuitions about the L2, while others access learners’ introspection. Also, some researchers (for example, Bickerton 1981) consider a feature has been acquired when it appears for the first time, while others (for example, Dully and Burt 1980) require the learner to use it to some predetermined criterion level of accuracy, usually 90 per cent. Thus, a distinction can be made between acquisition as ‘emergence’ or ‘onset’ and acquisition as ‘accurate use’. Clearly ‘acquisition can mean several very different things. This makes it very difficult to compare the results of one study with those of another. Conflicting results can be obtained depending on...