Cognitive linguistics implies an interacting function with environment. Language is thought of part of cognition and also has a symbolic character. The difference between language and other mental processes is a matter of degree. Language is symbolic because of its association between semantic representation and phonological representation.  This relationship refers to the Saussurian concept of linguistic sign.  However, it differs on one important point: the arbitrariness of the sign. Language is not structured arbitrarily; it is grounded in experience-physical, social, cultural experiences-in contravention of formalism. Consequently, blurring occurs between classical distinctions and dichotomies between literal and figurative language. Meanings develop from experience  and while using language, complex conceptual structures are involved. This idea that in linguistic meaning experienced-based knowledge is present implies no extant distinction between lexicon and grammar. Lexicon and grammar form a continuum, the premise of which is that they cannot be treated as autonomous modules as posited by Chomsky.  On this continuum, very specific concepts apply, that is, the lexicon for specific entities or relations.  Cognitive domains are the knowledge structures and mental representations about the world.  Both Lakoff  and Fillmore  refer to as the Idealized Cognitive Model (ICM). They both propose that one ICM is not adequate enough to define word meanings;  therefore, cognitive models must necessarily "combine to form a complex cluster that is psychologically more basic than the models taken individually."  Lakoff calls these "cluster models,"  implying that an arbitrary semantic category could not necessarily be described only by use of one cognitive model: many may be involved.  Imagination is considered central of rationality and defining conceptual meanings. The way we "reason and what we can experience as meaningful are both based on structures of imagination that make our experiences what it is."  These models have in common the development of "mental space."  Between these spaces must be element mapping. Fauconnier distinguishes between roles and values in mapping between these spaces. He sees a role as a linguistic description of a category; conversely seeing a value as an individual that can be described the category. 
Metaphor and metonymy  are basic cognitive mechanisms. In this application, they are viewed not as figures of speech, but are considered to be the means by which is it possible "to ground our conceptual systems experientially and to reason in a constrained but creative fashion."  Within this context, metaphor and metonymy are operationally defined as mappings between conceptual domains, and may be distinguished because connections made between things are different for each case.  While in metaphor, mapping is across different experiential domains, in metonymy, mapping takes place within the same domain.  Metaphor works by the similarity between two concepts, while metonymy works by the contiguity between two concepts. In metonymy, transfer of qualities from one referent to another does not happen as with metaphor. For example, the original meaning of "Westminster" is that of a city in Greater London; when metonymy is applied, the meaning shifts to the UK Government, which is located there.
Attempts to constrain metaphorical mapping is an ongoing problem.  Lakoff's "Invariance Principle" attempts to do so by having "metaphorical mappings preserve the cognitive topology of the source domain in a way consistent with the inherent structure of the target domain."  This Invariance Principle is useful in order to constrain the nature of those mappings; its only problem is that it does not show "exactly what part of the source domain should be the one that must be consistent with the target domain's structure." 
Evans attempted to construct a cognitive/realistic theory of lexical representation and programmatic theory of concept integration.  His position is that the organization of our language system is a function of how language is actually used.  He developed a "theory of lexical concepts and cognitive models,  claiming that there is a distinction between lexical concepts and meaning,  concluding that meaning, by itself, is not a function of language but arises from language use.
Cognitive linguistics rejects the substitution theory of metaphor; that is, where a metaphorical expression replaces a literal expression that has the same meaning.  They maintain that metaphorical meaning is a function of construing meaning, as a function of mapping across domains. 
A metaphor is . . . a conceptual mapping between two domains. The mapping is asymmetrical . . . the metaphorical expression profiles a conceptual structure in the target domain, not the source domain. . . . mappings . . . involve two sorts of correspondences, epistemic and ontological. The ontological correspondences hold between elements of one domain and elements of the other domain; epistemic correspondences are . . . relations holding between elements in one domain and . . . between elements in the other domain. 
Within cognitive linguistics, image schemas have not been precisely defined.  Grady proposes that image schemas are "related to recurring patterns of particular bodily experience, including perceptions via sight, hearing, touch, kinesthetic perception, smell . . ."  Dodge and Lakoff maintain that image schemas structure experience independently of language  They maintain that these schemas fit language to experience. Regier proposed the schemas are a function of specific neural structure.  However, his model did not support inferences.  The hippocampus is hypothesized to be involved in both episodic memory and for the processing of spatial information.  Recent studies found hippocampal-induced crosstalk with the ventromedial prefrontal cortex becoming a central node in representational networks over time, and if there is the existence of a prior associative schema, this facilitates the process.  Findings suggested that additional cross-talk between the hippocampus and the ventromedial prefrontal cortex is required to compensate for difficulties in integrating new information during encoding. 
Systemic functional linguistics focuses on language function. It is divided into metafunctions: ideational, interpersonal and textual. The ideational metafunction is further divided into two subelements, experiential-which orders experiences in the world, and logical-organizing reasoning on the basis of experience. The interpersonal metafunction modulates tenor (interactivity). Textual metafunction relates to the internal organization of and communication of text, referred to as mode.  Texts relate to its external context and internal cohesion.  Linguistic description is paramount. A typical approach is to apply a systemic parse; that is, a "functional description of a string of words that shows its constituency structure and corresponding collections of features selected from the grammatical system network."  Analysis of genre, that is, the words and structures that speakers us in language. Eggins maintains that this is a function of culture. 
When applied to multilingual studies, code-switching (substitution of a word or phrase from one language within a sentence in another language) and code-mixing (mixing of two or more languages is speech), translation shifts related to mood, subject person, deicticity (temporal vs. modal), and modal assessment may be observed. 
Language itself has been interpreted as a three-level semiotic system, where the semantic unit, unified through cohesive patterns, is the locus of choices in ideational, textual, and interpersonal meaning. These semantic choices, themselves derived from the need to express context in language, are in turn realized through lexico-grammatical choices, with each semantic dimension relating in a predictable and systematic way." 
Å½egarac and Pennington  address the issue of pragmatic transfer, which they describe as a culturally-modulated communication across two languages. They imply that this is related to functional linguistics because of the operations of choices between the speaker and receiver in terms of culturally-relevant communicative critera. 
Matthiessen maintains that language is inherently multimodal, that is, having the potential for three methods of expression: phonology, graphology and sign. He maintains that graphology and sign are visual, while phonology is perceived aurally or visually.  Mackenâ€‘Horarik explores symbolic abstraction within the context of systemic functional linguistics. She maintains that symbolic abstraction connects concrete motifs and abstract thematic, connecting metaphors. When students were asked to respond to an unseen narrative in open-ended way, they typically applied one of three strategies: "they speculate on the possible meaning of the narrative; they retell the story and explain its message, or they interpret its abstract significance, synoptically revisiting key events in the light of symbolic motifs."  She thus maintains that systemic functional linguistics provides a domain model of symbolic abstraction. 
Within systemic functional linguistics, the context of situation, with its subelements of field, tenor and mode have been used to describe language functioning. Muerier suggests that relationships between social practices within larger social structures are interdependent. 
Now, in comparing cognitive linguistics with systemic functional linguistics, cognitive linguistics typically does not address sense relation, such as hyponymy (incompatibility) or antonymy. 
Per Halliday, metaphor is seen "as variation in the expression of a given meaning, rather than variation in the meaning of a given expression."  See Table 1, below. "The idea of 'alternative realizations' inherently implies a conception of metaphor in terms of choice, a fundamental concept in SFL which is formalized by means of system networks." 
Traditional view: "from below"
New view: "from above"
Focus on lexical metaphor
Focus on grammatical metaphor
Metaphor as variation in the meaning of a given expression
Metaphor as variation in the expression of a given meaning
Comparison of the meanings of one lexeme (in different collocational cotexts
Comparison of various grammatical configurations as expressions of the same meaning
Literal versus metaphorical (transferred)
Meaning of a given lexeme
Degrees of (in) congruency: congruent and less congruent expressions of a given meaning
(realization inherently plays a role in lexical metaphor, but the concept is not used in the traditional view on metaphor
The feature of congruence applies to realizations of the same meaning
Table 1. Two perspectives on metaphorical variation