Well, first it is evidently that in individualised teaching (because learning is what the student does) is that you as teacher has only one student to handle, one student in full focus. It does not have to be an ideal situation anyway, if you as teacher can't understand the students learning difficulties, or is not knowledgeable and creative enough to help. But often ,it can be effective.
Differentiated instruction is very difficult. You have many students, you can't follow and analyze everthing everyone does, progresses or struggles with; human information processing capacity is limited. So you as a teacher focuses usually at the middle of the student ability scale, with some interventions now and then for the gifted to keep them somewhat stimulated, and for the ones struggling, trying to help a little. A very troublesome pedagogic situation, especially if what you teach is linear and hierachic in nature. Those who struggle will fall more and more behind whatever you do.
There is some hope, however, in learning analytics and adaptive learning, where information- processing algorithms and the teacher can work side by side. However, this makes present organisation by time and scheduling irrelevant, student progress in learning is what matters, independent of time. Instead of time as constant and learning variable, learning becomes constant and time variable. We may soon be there with help of ICTs who are not only of the documentation or communication kind, but of the information- processing kind.
Individualized learning is when the teacher focuses much on the distinctive needs of learners while striving to effect learning in them through intensive coaching as the students discover knowledge from the teaching and learning resources.
On the other hand, differentiated instruction happens when the instructor adjusts the same teaching content to suit the different learning abilities and levels of development of learners through the use of varied, efficient, and customized teaching and learning approaches.
Here are few resources that advocate for accommodating for the diverse backgrounds of students in differentiating learning according to the inforgraphic above:
Conference Paper Culturally Responsive ICT Integration into Teaching and Learning
Article Cultural Sensitivity Needed in Online Discussion Rubric Language
Article One Style Does Not Fit All: Facilitating Cultural Difference...
Article Integrating Cross-Cultural Elements Into Workforce Education...
Data Generation I: International and invisible in a workforce edu...
Data Curriculum Inclusiveness Challenge: Responding to Multicultu...
Differentiation is a whole class approach to inclusion. You are working with all students towards the same goals and the same assessment, and provide flexibility in pedagogical means/ multiple pathways. The term individualized learning generally implies that the curriculum is modified within individual targeted interventions. The student may spend time outside the class with a teaching assistant working on targeted individual remedial actions. There will be a degree of retrofitting provided to the individual student in order to compensate for what is identified as specific 'deficits'. There is an element of social capital and social inclusion that is inherently lost as the whole class approach is lost some of the time. Individualized learning is normally the result of an IEP. Personalized Learning in its original meaning (it has now been reclaimed by the tech discourse and means something entirely different more akin to UDL) would be the next notch away from differentiation: here there is no longer any attempt at integrating the student in whole class instruction; the curriculum is modified and assessment is altered for tailor made appropriateness. This blog I wrote my help: https://implementudl.wordpress.com/2015/09/13/udl-differentiated-instruction-personalized-learning-finding-ones-way-amongst-the-similarities-gaps-and-contradictions/