[...] - 'the farmer kills the duckling' - A rough [...] analysis discloses [...] three distinct and fundamental concepts [...] . We can visualise the farmer and the duckling and we have also no difficulty in constructing an image of the killing [...] the elements 'farmer', 'kill', and 'duckling' define concepts of a concrete order.
- Sapir (1921), a pag.82

The concreteness of experience is infinite, the resources of the richest language are strictly limited. It must perforce throw countless concepts under the rubric of certain basic ones, using other concrete or semi-concrete ideas as functional mediators.
- Sapir (1921), a pag.84

Some concrete concepts, such as 'kill', are expressed radically; others, such as 'farmer' and 'duckling', are expressed derivatively. Corresponding to these two modes of expression we have two types of concepts and of linguistic elements, radical ( 'farm', 'kill', 'duck' ) and derivational (' -er', '-ling' ).
- Sapir (1921), a pag.84

What [...] are the absolutely essential concepts in speech [...]? Clearly we must have [...] a large stock of basic or radical concepts, the concrete wherewithal of speech. We must have objects, actions, qualities to talk about, and these must have their corresponding symbols in independent words or in radical elements.
- Sapir (1921), a pag.93

Basic (Concrete) Concepts (such as objects, actions, qualities): normally expressed by independent words or radical elements: involve no relations as such.
- Sapir (1921), a pag.101

It is possible for a concrete concept, represented by a simple word, to lose its material significance entirely and pass over directly into the relational sphere without at the same time losing its independence as a word.
- Sapir (1921), a pag.102