This thesis deals with the topic of programming linguistics. A survey of the current techniques in the fields of syntax analysis and semantic synthesis is given. An extensible automatic translator has been described which can be used for the automatic translation of a class of programming languages. The automatic translator consists of two major parts: the syntax analyser and the semantic synthesizer. The syntax analyser is a generalised version of LL(K) parsers, the theoretical study of which has already been published by Lewis and Stearns and also by Rosenkrantz and Stearns. It accepts grammar of a given language in a modified version of the Backus Normal Form (MBNF) and parses the source language statements in a top down, left to right process without ever backing up. The semantic synthesizer is a table driven system which is called by the parser and performs semantic synthesis as .the parsing proceeds. The semantics of a programming language is specified in the form of semantic productions. These are used by the translator to construct semantic tables. The system is implemented in SN0B0L4 (SPITBOL version 2.0) on an IBM 360/44 and its description is supported by various examples. The automatic translator is an extensible system and SN0B0L4, the implementation language appears as its subset. It can be used to introduce look ahead in the parser, so that backup can be avoided. It can also be used to introduce new facilities in the semantic synthesizer.