History ( forward n - gram ) or Future ( backward n - gram ) ? Which model to consider for n - gram analysis in Bangla ?

This paper presents a directional advantage of n-gram modeling in terms of backward or forward n-gram modeling in Bangla. The most commonly used n-gram analysis is predominantly a forward n-gram. However in Bangla it appears that a backward n-gram is repeatedly more successful and yields more grammatical results than a forward n-gram. This paper hypothesizes that the rationale behind this success is the syntactic ordering of constituents in Bangla. Bangla is a headfinal specifier-initial language as opposed to English, which is head-initial specifier-initial. Hence in Bangla, the head comes after its argument in a phrase. If an ngram analysis begins with a head and moves backwards it will stretch to its own argument but if you move forwards then you'll probably grab the argument of another head. As probability of occurrence of heads is higher, probability of depending on a head is also higher and hence a backward n-gram will probably have a greater chance of yielding grammatical results. We carried out several experiments to compare different directional results in different applications with an advantage in the backward direction. This will prove a useful linguistic insight in terms of n-gram based analysis depending upon variations of constituent analysis.