As 172_driver points out, the only standard that really matters is the one that applies where you happen to be flying. Controllers, being the flexible and versatile souls that they are, will normally cope with pilots using variations that are used elsewhere but will stick to the local standard themselves.
ICAO provides a baseline of phraseology and terminology in Annex 10 and PANS-ATM and offers guidance in the Manual of Radiotelephony which gives examples of how the phraseology is used in a variety of practical situations. ICAO recognises that these phraseologies will not suit every situation and in Doc 4444 says
They [the examples] are not intended to be exhaustive, and when circumstances differ, pilots, ATS personnel and other ground personnel will be expected to use plain language, which should be as clear and concise as possible....
The Manual of Phraseology also says
ICAO phraseologies are developed to provide maximum clarity, brevity, and unambiguity in communications. Phraseologies are applicable to most routine situations; however, they are not intended to cover every conceivable situation which may arise. The success and widespread adoption of the ICAO phraseologies has given rise, to some degree, to an expectation on the part of some users that phraseologies alone could suffice for all the communicative needs of radiotelephony communications. ICAO provisions related to the use of language adopted by the ICAO Council in 2003 better clarify that, while ICAO phraseologies should always be used whenever they are applicable, there also exists an inherent requirement that users also have sufficient "plain" language proficiency.
The variations in phraseology, such as where the callsign goes, is far less important than communicating effectively. It is sometimes frustrating to see people struggling to find some standard phrase (or arguing about which should be used) to cover a non-standard situation which they ultimately fail to explain - and when plain language might have been far better.