Using feature learning for a medical text classification problem I'm currently working with the CHILDES corpus trying to create a classifier that distinguishes children whom suffer from specific language impairment (SLI) from those who are typically developing (TD).

In my readings I noticed that there really isn't a convincing set of features to distinguish the two that have been discovered yet, so I came upon the idea of trying to create a feature learning algorithm that could potentially make better ones.  

Is this possible? If so how do you suggest I approach this? From the reading I have done, most feature learning is done on image processing. Another problem is the dataset I have is potentially too small to make it work (in the 100's) unless I find a way to get more transcripts from children.
Having just looked through a few entries from the corpus, I'd personally be skeptical of the applicability of any naive approaches.


In particular light of your small training set, I'd recommend that
whatever method you use should be able to produce human-readable
explanations for the operation of the classifier it builds (e.g.
decision trees/learning classifier systems/genetic programming):
this allows 'common sense' tuning of the classifier, rather than the
danger of overfitting to the training set via black box parameter
optimization.
Rather than throw the entire 'bag of words' at a classifier and hope
that the appropriate set of features will be extracted, you should
first consider what kind of criteria you as a human being might use
to make that decision, and how you might be able to pre-process to
produce features (e.g. syllable-length, metrics from ConceptNet etc) that
are as close to these as reasonably possible.
Having used some human intuition to obtain a reasonable set of
feature primitives, then you can build your classifier and obtain
higher-level expressions that discriminate between them.