Adding Phase 1 description to readme

Author: achimr

README.md

@@ -1,3 +1,17 @@
 # DataCollection
 
+Collecting data for machine translation training from CommonCrawl is a two-phase process illustrated in the following diagram:
+
 ![CommonCrawl process diagram](/common_crawl_process.png?raw=true "CommonCrawl data collection process")
+
+## Phase 1: Language annotation, building a meta-data database and monolingual data extraction
+
+The first phase detects the languages of the web pages contained in the crawl and other meta-data. A database is built from this data that can be accessed via a RESTful web API.
+
+In this phase monolingual data for language model training can be generated. The data for some of the CommonCrawl crawls and some languages can be found on:
+
+* http://statmt.org/ngrams/
+* http://www.statmt.org/wmt16/translation-task.html
+
+For more details on the monolingual data see [ModernMT Deliverable 2.1](http://www.modernmt.eu/deliverables/mmt-d2-1-report-on-data-repository/).
+