The purpose of this dissertation is to explore the nature of intervention effects seen in various constructions like Wh-scope marking, raising and passivization. In particular, this dissertation argues in favor of a movement account for all these cases and supports the idea that (syntactic) movement is inevitable and sufficient enough to provide a unified account of various structural relations (Hornstein, 2009). It further argues that movement always happens in narrow syntax, even when it isn't visible. For some of these invisible cases, this dissertation suggests head movement as an alternative to LF movement and Agree.

The second aim of this dissertation is to explain intervention effects in terms of relativized minimality (Rizzi 1990, 2004). In this consideration, this dissertation sides with Boeckx & Lasnik (2006) view that not all minimality violations are derivational: some are repairable, indicating that they must be treated as representational constraints, while others are not, indicating that they are derivational.

In this study, the dissertation not only reviews cross-linguistic facts from languages like English, German, Chinese, Japanese, and Icelandic but also provides novel empirical data from Hindi/Urdu. This way, the dissertation focuses on cross-linguistic as well as language specific investigation of intervention effects. The third aspect of this dissertation therefore is to relate cross-linguistic variations in intervention effects to the difference in the nature of the phase heads among languages. For instance, the cross-linguistic difference in the properties of various constructions (such as Wh-scope marking and double object construction) is reducible to the availability of an escape hatch with the relevant phase head (C or v).

In this exploration, this dissertation also makes two language specific claims about Hindi/Urdu; (a) the basic word order in this language is SVO, and (b) this language involves Wh-movement in overt syntax. The first claim contributes to the long standing debate about the basic word in Hindi/Urdu, a language which shows a dichotomy in its word order by exhibiting both SOV and SVO word order. The second claim adds to the covert vs. overt Wh-movement debate for Wh in-situ languages like Hindi/Urdu. The dissertation attributes both these aspects to the phasehood of little v in Hindi/Urdu.