Pre-Catastrophe, English was spoken, though it would little resemble the English that we recognize and use. Years of change, especially as a result of the schooling system and the integration of many new cultures and ideas radically altered the structure of the language. The language changed rapidly, and adopted many different dialects based primarily on location. Colloquialisms were common, and swiftly changing in meaning and purpose. Other languages were widely used, but English was used as the main communication form.
Post Catastrophe, the old English forms were quickly discarded in favour of the language used in the printed books sent by the unknown group from Earth. Other languages like Latin were preserved in a similar fashion. Owing to a lack of storage space and owing to the need to transmit the necessary information for living, only English [and the occasional Latin] texts were sent, or perhaps were the only ones recovered or preserved..
In the early years, Pre-Catastrophe English was spoken, but was quickly supplanted by the ancient forms, as they were written and had more concise and simple structures. The latest English teaching text in use dated from the middle part [roughly 1940 or so] of the 20th century. The language did not change rapidly, and the new education systems could better cope with instructing in it. Now referred to as Modern, Post-Catastrophe or Standard English, it is used throughout the Colony.
The only additions to Standard English were words used to describe devices or attributes not found in the texts of that time. These words were frequently derived from Latin or a different language believed to be Greek. Hence, words like nano-technology or semi-conductor entered the language.
Where colloquialisms exist, they are well noted and recorded in their usage, many derive themselves from colloquialisms found in the ancient texts. Other languages have sadly been either forgotten, or reconstructed in fragments from memory and their existence in the ancient texts. This is regarded as a tremendous tragedy, as experts estimate that Earth society had at least ten different spoken and written languages, though only two remain in full form [Latin, English], one partial [Greek], and two in fragmentary form [Unknown- European Continent and Unknown- Eastern Asian Continent]. There are fragments of perhaps other languages used in the English language as well, though many appear to be older forms.
Pre-Catastrophe English has been preserved and is studied by experts involved in ancient artifact recovery operations. Very few people can speak it now.