It is interesting how specialists all over the world are trying to define CLIL. The first definition was written by the European Commission and tried to consider it as an “umbrella term”. In 2002 David Marsh provided the (probably) most quoted description:
CLIL refers to situations where subjects, or parts of subjects, are taught through a foreign language with dual-focused aims, namely the learning of content, and the simultaneous learning of a foreign language.
Little by little the “umbrella” seems to be described more accurately, as teachers become more familiar with CLIL in practice. In other words, practice is shaping the concept of CLIL , and it is helping to determine what can be considered CLIL and what it is not, by any means, teaching through a foreign language.
An example of this is the distinction between soft and hard CLIL I’ve come across thanks to the work of Keith Kelly and Phil Ball. Soft CLIL stands for teaching content through the medium of a foreign language but with predominantly linguistic objectives. Teachers involved in soft CLIL will put language issues in front of their syllabus, and use content to give a framework for them. In my opinion, this is a more EFL version of CLIL, as most EFL teaching in the last decades has been topic-based but language oriented. Different methodological techniques may apply, though.
On the other hand, hard CLIL stands for teaching content through the medium of foreign language with content objectives at the front. That is, language is relevant as much as it is needed to progress in the learning of content, but THERE IS, and MUST BE, language awareness, more specifically at the level of discourse and functional language.
After seven years working on researching and studying bilingual education, I am more inclined to consider the definition of hard CLIL much closer to my idea of what integrating content and language is. If we really want to use any foreign language as a communicative tool in the classroom, content cannot be enslaved to language. Quite the contrary, the real integration appears when we are able to determine which language we need to help our students to access that content, to work with it, analyse it, assimilate it, and create with it. That’s my view.
Further reading on the definition of CLIL What is CLIL? by Phil Ball (onestopenglish)