From the langscape project's results:
Most interesting among all the responses on suffixed words were those for words ending in -ment, where usage in some places is inclined to remove the medial e, at least in acknowledgment and judgment. This runs counter to the general rule for suffixes beginning with a consonant (whereby the e is retained as in advertisement). However legal usage has long preferred judgment. The overall response was an endorsement of the rule by large majorities: abridgement (80%), acknowledgement (73%), judgement (76%), lodgement (83%). The publishers' common practice of titling their "acknowledgments" page with the e-less form seems therefore to be out of step with a large body of English users. The responses from England, L2 Europeans and from Australians were all alike on this; however American respondents stood apart in their preference for e-less forms. If you want to take part in the project the on-line component is at:
http://www.shlrc.mq.edu.au/langques/Bingley
