In the literature of aspectual acquisition, the interaction between grammatical aspect and lexical aspect has been widely investigated (cf. Robison 1995, Bardovi-Harlig and Reynolds 1995, Anderson 1991, Anderson and Shirai 1996, Collins 2002). Grammatical aspect, also called viewpoint aspect, enables people to talk about a situation from different aspectual perspectives via different grammatical morphemes (Anderson 1991, Bardovi-Harlig 2000, Li and Shirai 2000). Sentences (5a) and (5b) illustrate two kinds of viewpoints on the event of making a toy house.
(5) a. Sam made a big toy house for Jessie.
b. Sam was making a big toy house for Jessie. (Li and Shirai 2000:1) Sentence (5a) implies that the action of making the big toy house was completed;
that is, the toy house has already been made. On the contrary, (5b) simply states the fact that Sam was engaging in making the toy house without indicating whether the action was completed or not. The different semantic interpretations of (5a) and (5b) arise from the difference in aspect markings. The past morpheme in (5a) indicates the completion of the event while the progressive marking in (5b) emphasizes action in progress.
Lexical aspect, also known as situational aspect or inherent aspect, deals with the inherent semantic properties of the verbs or verb phrases which describe situations (Anderson 1991, Bardovi-Harlig 2000, Li and Shirai 2000). For instance, notice is
inherently punctual and know is inherently durative. In the literature of aspectual acquisition, the most widely adopted classification of the lexical aspect of verbs is Vendler’s (1957) four-way distinction of states, activities, achievements, and accomplishments (cf. Bardovi-Harlig 1992, Bardovi-Harlig and Reynold 1995, Bardovi-Harlig and Bergström 1996, Rohde 1996, Shirai and Kurono 1998, among others). Of the four classes, states and activities encode no inherent endpoints while accomplishments and achievements do. In addition, only states are not dynamic and achievements different from all the other in that they have no duration.
Both lexical aspect and grammatical aspect contribute certain amount of information to the aspectual interpretation of a sentence. Therefore, language learners have to acquire the meanings and uses of not only lexical aspect but also grammatical aspect. According to Li and Shirai (2000), although lexical aspect is relatively similar across languages, grammatical aspect varies. Aspectual forms with the same name can encode different ranges of meanings in different languages. As illustrated in Section 1.1, although English –ing and Chinese zai both signal progressive aspect, –ing can combine with more verb types than zai. Thus, Chinese learners of English have to acquire a wider range of uses of L2 progressives which are different from their L1.
Literature has shown that L1 exerts influence in the acquisition of L2 (Fries 1945, Weinreich 1953, Lado 1957). Proponents of Contrastive Analysis (Fries 1945, Weinreich 1953, Lado 1957) claim that learning difficulties can be predicted by comparing the linguistic differences between L1 and L2. Elements that are similar in L1 and L2 bring about positive transfer while those that are different result in negative transfer. However, Stockwell, Bowen, and Martin (1965) have proposed a hierarchy of difficulty in L2 acquisition regarding the structure or semantic correspondence between L1 and L2. This hierarchy includes five levels of difficulty: split, new, absent,
coalesced, and correspondence3, which shows that the prediction of learning difficulties may not always be so straightforward.
Different from those who believe in L1 influence, some researchers have proposed the Aspect Hypothesis, which states there is a universal sequence in L1 and L2 acquisition of tense-aspect morphology (Shirai 1991, Anderson and Shirai 1994, Shirai and Anderson 1995, Anderson and Shirai 1996, Li and Shirai 2000). The Aspect Hypothesis is originally formulated on the basis of some consistent findings in L1 acquisition that children’s early use of grammatical aspect markings is highly correlated with lexical aspect (Bronckart and Sinclair 1973, Antinucci and Miller 1976, Bloom, Lifter, and Hafitz 1980). Children from diverse language backgrounds were found to use aspectual markers almost exclusively with certain verb types at initial stages of development. It was at later stages that they gradually extended their aspect markings to other verb types. Based on these findings, four predictions concerning the development of form-meaning association have been generated (Shirai and Anderson 1995, Anderson and Shirai 1996, Li and Shirai 2000):
i) Learners first use past marking on achievements and accomplishments, eventually extending use to activities and states.
ii) In languages that have perfective-imperfective distinctions, imperfective past appears later than perfective past. Imperfect past marking begins with states and activities and then extends to accomplishments and achievements.
iii) In languages that have progressive aspect, progressive marking begins with activities, and then extends to accomplishments and achievements.
3 According to Stockwell, Bowen, and Martin (1965), split is expected to be the most difficult to acquire, followed by new, absent, coalesced, and correspondence, in descending order of difficulty.
Split: A single form in L1 splits into two or more forms is L2, e.g. kan in Chinese splits into see, watch and look in English. New: A form that is absent in L1 but present in L2, e.g. Chinese does not have a tense system but English does. Absent: A form that is present in L1 but absent in L2, e.g. Chinese has the ba-construction while English does not. Coalesced: Several forms in L1 collapse in L2, e.g.
Chinese classifiers collapse into a/an in English. Correspondence: One form in L1 maps to one form in L2, e.g. Chinese bi and English pen.
iv) Progressive marking is rarely incorrectly overextended to states (in L1 acquisition).
Shirai and Anderson (1995) have proposed a prototype account for the acquisition sequences. L1 or L2 learners’ uses of tense-aspect morphology begin with the prototypes of a given morphological category and later spread to more peripheral members. To illustrate, action in progress is considered to be the prototypical meaning of progressive, so L1 or L2 learners first associate it with activity verbs which possess the feature of dynamicity and durativity. In the same vein, since the perfective or past markings prototypically indicate completion, they are easily applicable to verbs that encode result.
Though originally generated from results of L1 studies, the Aspect Hypothesis has drawn a great deal of interest in L2 research (Bardovi-Harlig 1992, Bardovi-Harlig and Reynold 1995, Robison 1995, Bardovi-Harlig and Bergström 1996, Rohde 1996, Shirai and Kurono 1998, Huang 1999, Collins 2002, Salaberry 2002, among others). The L2 studies generally agree with the Aspect Hypothesis in terms of L1 or L2 learners’ biased use of grammatical morphemes. Like L1 learners, L2 learners also show a strong preference for marking progressive aspect on activities and past marking on achievements at the incipient stages of acquisition. However, disagreement exists in whether they gradually expand their aspectual markings to all types of verbs as they advance in subsequent stages. Some studies have found that more advanced L2 learners would not restrict their tense-aspect marking to certain verb types (Bardovi-Harlig 1992, Bardovi-Harlig and Reynold 1995). That is, L2 learners were capable of using tense-aspect morphology with various types of verbs as they became more proficient. On the contrary, other researchers have reported an opposite pattern where L2 learners at a higher level of proficiency showed a tighter association between lexical aspect and grammatical aspect (Robison 1995,
Bardovi-Harlig and Berström 1996, Rohde 1996, Salaberry 1999). In other words, higher level L2 learners tended to use past marking predominately on achievements and use progressive marking on activities. Because of the conflicting results, further investigation on L2 aspectual acquisition is still necessary.
In addition to the temporal properties of verbs or verb phrases, agency of a subject in a sentence may also play a role in L2 acquisition of progressive aspect. In English, the progressive aspect can take an agentive subject as in (6a) and a non-agentive subject in (6b).
(6) a. Mary is singing.
b. The ice cream is melting.
Although both Mary and the ice cream are subjects, their thematic roles are different. Mary is an agent for she has control over the action of singing while the ice cream is a not because it simply undergoes the action of melting. Previous studies on the history of English progressives have revealed that English progressive aspect is initially applicable to only an agentive subject and expands to include a non-agentive subject at later stages of grammaticalization in Modern English (Hopper and Traugott 1993, Bybee et al. 1994, Smitterberg 2002). The diachronic development of language has been found to have a parallel in language acquisition. It is confirmed that there are cases in which L2 learners’ acquisition sequence of the target language follows the historical change of language (Giacalone Romet 1992, Comajoan and Saldanya 2005).
Furthermore, according to Givón (1984:139), there is a thematic hierarchy for the subject position: agent>recipient/benefactive>theme/patient>location>instrument. It is most natural for an agent to occur in the subject position. This hierarchy, as well as the diachronic development mentioned above, may provide a prediction for the acquisition order of English progressives.
Aside from the linguistic properties, task effects have also been discussed in the
acquisition research (Larson-Freeman 1976, Tarone 1985, Rothman 2007). It is important to examine how different task formats affect L1 or L2 learners’
performance and whether the results from the two tasks pattern consistently (Sugaya and Shirai 2007, Muñoz and Gilabert 2011). Another issue that relates to task effects is the relationship between comprehension and production tasks (Tarone 1985, Tarone and Parrish 1988, Tasseva-Kurktchieva 2007, Hendriks and Koster 2010). While some studies observed a relatively similar tendency in comprehension and production tasks (e.g. Sugaya and Shirai 2007), others found different acquisition orders in the two tasks (e.g. Tasseva-Kurktchieva 2007). Given this, the present study employs both comprehension and production tasks to examine the relationship between the two.
Moreover, L2 proficiency has been found to be a possible factor affecting learners’ performances (Kellerman 1983, Sasaki and Hirose 1996, Ho 2008, Gabriele 2009, Liu 2011, Sawetaiyaram 2012). Some studies reported a U-shape behavior exhibited by L2 learners at elementary, intermediate, and advanced levels (e.g.
Kellerman 1983). Namely, the accuracy rate of their elementary and advanced subjects was high but that of the intermediate subjects was low. However, other studies showed that the accuracy rates of L2 learners’ responses increased with their proficiency level (e.g. Ho 2008, Liu 2011). In view of the inconsistency, the present study also examines the variable of L2 proficiency.