The most proficient language users, namely bilinguals, favor inter- and intrasentential CS which "require most knowledge of both languages" (Poplack 1980:606) whereas tag-switched sentences are preferred by less proficient and non-bilingual speakers who, in comparison to their first language, are less competent in their second language. 3. Grammar of Intrasentential Code Switching

As already mentioned in chapter 2.2.1 the switching of languages within a single sentence is no random occurrence. As many researchers observed that "bilinguals tend to switch intra-sententially at certain (morpho) syntactic boundaries and not at others" (Poplack 2004:1). According to Poplack (2004:1) the government of grammatical constraints on CS has become a largely accepted fact. "Though, there is little consensus on what they are or how they should be represented" (Poplack 2004:1). The question arises in which way two separate grammars merge to one grammatically correct sentence and which grammar governs the switching. The following chapter gives an overview of the most prominent theories of CS grammar.

3.1 One Grammar

MacSwan (2000:42) asserts that all theories which try to impose grammatical constraints on CS have conceptual and empirical shortcomings. However, two common threads emerge which should be mentioned. According to MacSwan (2000:42) "Poplack (1980) and Belazi et al. (1994) share an intuition that a basic conflict in the requirements of the mixed grammars is responsible for ungrammaticality in code switching, an appealing idea, which, as I will try to illustrate below, could prove extremely fruitful in the analysis of code switching data." Additionally, MacSwan (2000:42) explains that "Mahootian (1993) and Belazi et al. (1994) have both insisted that there are no constraints which operate on code-switched constructions which do not also operate on monolingual constructions, a suggestion which goes back at least as far as Woolford (1983). Despite this, both frameworks proceed to formulate arbitrary limits on the range of grammatical apparatus relevant to bilingual code switching (namely, the complement relation). In the absence of evidence, there is no reason to limit the range of grammatical relations that interact with code switching. In fact, data considered so far constitutes strong evidence that this relation alone cannot account for all of the facts of language mixture."

The basic premise of the One Grammar or Minimalist theory of CS grammar is: "Nothing constrains code switching apart from the requirements of the mixed grammars" (MacSwan 2000:43). In other words, all of the facts of code switching may be explained just in terms of principles and requirements of the specific grammars used in each specific utterance.

Therefore, MacSwan (2000:43) presents a Minimalist Program "whose basic mechanisms consist not in the operation of rules of grammar which apply specifically in code switching contexts, but in a principled consideration of ways in which discrete components of the grammar are allowed to interface in bilingualism." Thus a minimalist approach to code switching (which adheres to the agenda) might posit that lexical items may be drawn from the lexicon of either language to introduce features into the numeration, which must then be checked for convergence in the same way as monolingual features must be checked, with no special mechanisms permitted. In this lexical approach, no control structure or code switching-specific rules are required to mediate contradictory requirements of the mixed systems. The requirements are simply carried along with the lexical items of the respective systems. Thus, it makes sense to formalize the grammar used for code switching as the union of the two lexicons with no mediating mechanisms.

MacSwan (2000:43) describes two central components to the Minimalist Model: "CHL, a computational system for human language, which is presumed to be invariant across languages, and a lexicon, to which the idiosyncratic differences observed across languages are attributed." Additionally MacSwan (2000:43) suggests that "phrase structure does not vary across languages; surface differences in word order relate only to the re-arrangement of elements in the syntactic tree as the result of movement operations, triggered by lexically encoded morphological features."

MacSwan (2000:43) describes this as the Select, Merge, Move operation. According to MacSwan (2000:43): "An operation, which may be called Select, picks lexical items from the lexicon and introduces them into the numeration, an assembled subset of the lexicon used to construct a derivation. Another operation, Merge, takes items from the numeration and forms new, hierarchically arranged syntactic objects (substructures). The operation Move applies to syntactic objects formed by Merge to build new structures."

Therefore, in the Minimalist Program, phrase structure trees are built derivationally by the application of the three operations Select, Merge and Move, constrained only by the condition that lexically encoded features match in the course of a derivation. (Seite...

This makes a rather different conception of bilingualism possible, since it is no longer necessary to regard grammars as compartmentalized in some way in the language faculty. In the minimalist framework, CHL is invariant across languages, and the Lexicon does not need to be privy to sociopolitical distinctions like Spanish, Nahuatl, and Chinese."
According to MacSwan (1997: 174) "the central, leading aim of Chomsky's (1995a) minimalist program is the elimination of all mechanisms that are not necessary and essential on conceptual grounds alone; thus, only the minimal theoretical assumptions may be made to account for linguistic data, privileging more simplistic and elegant accounts over complex and cumbersome ones." Therefore, theories of code switching which make use of independently motivated principles of grammar are favored over those which posit rules, principles or other constructs specific to it (MacSwan 1997: 174).

3.2 Two Grammars

An alternate explanations for how grammar combines in CS is the theory of two grammars. Under this model, "the grammars of the two languages are not altered in any way; no hybrid rules of any sort are created. The two grammars operate during code-switching just as they do during monolingual speech, except that each grammar generates only part of the sentence" (Wooford 1983: 522). Figure 3 provides partial representation of a model of how two monolingual grammars co-operate to generate codeswitching sentences.

Figure 3 (Woolford 1983:523).

According to Woolford (1983:523) phrases that occur in the overlap cannot be distinguished grammatically as either of the contributing languages (Spanish and English in this case, but actually simultaneously belong to both grammars. Woolford (1983:523) explains that, "This area of overlap between the two phrase structure components should be thought of as a sort of space warp that allows one speaker to be in two universes, or two grammars, at once. The lexicons and word formation components of the two grammars remain entirely separate from each other. That is, English lexical items fill terminal nodes created by English phrase structure rules; likewise, the Spanish lexicon inserts lexical items into terminal nodes created by Spanish phrase structure rules."

Woolford provides several examples:

(1) I put the forks en las mesas. (McClure (1977))

'I put the forks on the tables.'

"Example (1) is a syntactic construction common to both English and Spanish; it is generated entirely by common phrase structure rules from the area of intersection of the two phrase structure components" (Woolford 1983:524).

(2) Todos los Mexicanos were riled up. (Pfaff (1979))

'All the Mexicans were riled up.'

"In (2) the subject NP is filled entirely in Spanish (although the structure is common to both languages), while the rest of the sentence is in English" (Woolford 1983:524).

(3) No van a bring it up in the meeting. (Pfaff (1979))

'They are not going to bring it up in the meeting.'

"In (3) the sentence begins in Spanish, switching to English in the embedded VP" (Woolford 1983:524).

(4) El hombre who saw the accident es cubano. (Gingras (1974))

'The man who saw the accident is Cuban.'

Example (4) involves two code switches. The embedded clause is English, but the rest of the sentence is Spanish. (Woolford 1983:524).

(5) En Puerto Rico he would say que cortaba cania, even though tenia su negocio, you know. (Sankoff and Poplack (1980))

'In Puerto Rico he would say that he cut cane even though he has his own business, you know.'

Example (5) involves switches at several major constituent breaks.

Poplack (1979) establishes that there is no word-internal code-switching, and pro-poses a surface structure constraint to this effect. The impossibility of word-internal code-switching follows directly under this model from the fact that the autonomous word formation components remain separate and do not interact in any way. The two monolingual grammars cooperate in the production of code-switched utterances, but none of the rules of either grammar are altered in any way. Phrase structure rules are drawn freely from both grammars during the construction of constituent structure trees, but the lexicon of each grammar is limited to filling only those terminal nodes created by phrase structure rules drawn from the same language. Nevertheless, in the event that there are phrase structure rules common to both languages, such rules belong simultaneously to both languages. Lexical items can be freely drawn from either language to fill terminal nodes created by phrase structure rules…