While the Bible is a reference used in our worship it is far from our most prominently used publication. Of the approximately four hours per week of group worship engage in at our local places of worship (Kingdom Halls), routinely the Bible, by itself, is only discussed for 10 min. The remaining 230 min. of weekly instruction is culled entirely from Jehovah’s Witnesses publications with their own unique concepts and phraseology. Peppered throughout these publications are many scriptural citations but the bulk of the text is from writers originating at the world headquarters in New York.
In fact Jehovah’s Witness publications refer to this unique way of speaking as ‘the pure language’ stating principally that “The pure language is the truth about Jehovah God and his purposes as found in his Word, the Bible.” (Watchtower August 15, 2008) Secondarily, the article goes on to parallel learning an actual spoken language and this ‘language of concepts’ saying, “Imitate fluent speakers. Students of a new language are encouraged not only to listen carefully but also to try to imitate, or mimic, the pronunciation and speech patterns of fluent speakers. This helps the students to avoid developing a heavy accent that may later hinder their efforts to communicate. In a comparable way, we should learn from those who have mastered the “art of teaching” the new language.” (Reference: http://wol.jw.org/en/wol/d/r1/lp-e/2008604)
This ‘imitation’ is I believe what the original questioner was getting at. Those who are the main speakers in the congregation and at our larger conventions use phraseology that is unique to the religion and those who aspire to someday be in their position imitate this speech. The lay members of the congregation adopt the speech because this is what they are hearing from those speaking and what they are reading in the Jehovah’s Witnesses’ publications. Phrases such as ‘field service,’ ‘theocracy,’ ‘remnant,’ ‘governing body’ are products of our religious beliefs but certainly not concepts or terms Jesus Christ used.
Another Jehovah’s Witnesses publication entitled Theocratic Ministry School Guidebook acknowledges this quite clearly, stating on page 112: “Our study of the Scriptures and the Watch Tower Society’s publications has given us a vocabulary of terms quite strange to those unacquainted with our work. If we were to explain the truths of the Bible to some audiences, using such terms as these, either much of what we say would be lost or our speech would be entirely unintelligible.” (Reference: https://wol.jw.org/en/wol/d/r1/lp-e/1101971070#h=20)
In response to @4castles comment: It is disingenous to overstate the impact the Bible has on the Jehovah’s Witnesses vernacular versus the impact of Jehovah’s Witnesses publications. As mentioned earlier in this post, yes, the publications are peppered with scriptures, however they are re-framed in the JW vernacular.
In other words JW publications often cite a scripture, then translate the ideas of that scripture into vocabulary that Jehovah’s Witness have become accustom to. Again, with the exception of approximately 4 minutes of Bible reading all of the scriptural discussion for both meetings are facilitated via workbooks, outlines, prepared videos and publications. Generally the content of the workbook and outlines are expected to be adhered to closely.
This is the case for those presenting at Jehovah’s Witnesses annual conventions as well. The material originates from world headquarters and is heavily scripted. From experience, these outlines (scripts) are expected to be adhered to closely. I think it’s safe to say that we make the statements: “The Society (meaning the group of individuals responsible for writing the various publications) says” or “The Watchtower (the magazine) says” or “The publications (books writen by the JW oranization) say” just as often as we state “The Bible says.”
Specific portions of our services are set aside for demonstrating and practicing what we will say when preaching in the local neighborhoods. While encouraged to make these discussion our own, chatting extemporaneously with a stranger is not easy for most. Naturally most JWs fall back on a rehearsed sermon — that is exactly what the OP is hearing when talking to JWs.