Since October 2015, the openCypher project has aimed to provide an open grammar, language specification, technical compatibility kit and reference implementation of parser, planner, and runtime for Cypher.
This is how the Neo4j website presents openCypher. Not only is this query language awesome, but this initiative of freeing it means that knowing Cypher does not limit you to only one vendor, be it the best graph database of the market or otherwise. This is intrinsically good for you. Currently, the other vendors involved in the openCypher project are Oracle, Apache Spark, Tableau, and Structr, but there are, of course, open source projects coming from the community. These projects may not offer the full language and may make use of other databases to persist data, such as PostgreSQL or Redis.
The openCypher website is http://www.opencypher.org.