Table 1. A summary of the aims and methodological approaches (sample size and tasks used to manipulate language and working memory (WM) of the 20 studies included in this review.

Authors (year)	Aim of studies	Participants		Tasks
		Experimental group	Control group	Language	Working memory
Buchweitz et al. (2009) [16]	Brain activation for listening and reading comprehension processes & individual differences in WM capacity	N = 12	N/A	Auditory and visual sentences' comprehension	Reading span task: rapid serial visual presentation format (RSVP)
Moore et al. (2013) [72]	Study of a model of verbal WM with specific focus on basal ganglia. Potential differences in neural function across the complete process of verbal WM	N = 14	N/A	Identification of semantic relationship between 2 words in a pair	Verbal WM task
Buchweitz et al. (2012) [97]	Brain activation in dual task vs single-message comprehension & individual differences in WM capacity	N = 12	N/A	Single vs. two concurrent spoken sentences comprehension	Reading span task: rapid serial visual presentation format (RSVP)
Fiebach et al. (2004) [98]	Neural correlates of syntactic ambiguity & individual differences in WM capacity.	N = 15 (divided in 2 groups)	N/A	Temporarily ambiguous sentences	Reading span task
Mason & Just (2007) [99]	Changes to cortical networks in processing ambiguity & individual differences in WM capacity.	N = 12	N/A	Lexical ambiguity task	Reading span task
Rudner et al. (2013) [102]	Neural representation of language modality specificity (semantic, phonological and orthographic) processing in WM	N = 20 (hearing non-signers)	N = 11 (deaf signers)	2-back task conditions according to Semantic, Phonological, Orthographic and Colour baseline criteria	2-back task: 4 different linguistic conditions
Rudner et al. (2005) [103]	Neural correlates of mentally reversing spoken items (and comparison with a rhyme judgment task)	N = 12	N/A	Auditory word reversal task	Rhyme judgment task
Newman et al. (2013) [104]	Impact of WM capacity on sentence comprehension, task activation and connectivity between language and WM-related regions	N = 50	N/A	Sentence comprehension task, varying syntactic complexity	Reading Span task
Wallentin et al. (2006) [110]	Neural correlates of efficient involvement of WM systems during language comprehension	N = 21	N/A	Spoken sentences comprehension and verbally-cued recall	Spatial and nonspatial recall of image elements
Marvel & Desmond (2012) [112]	Neural correlates of inner speech processes related to manipulating versus storing verbal content during WM	N = 16	N/A	Letter recognition and recall (using a probe) task	Verbal WM task: Sternberg task
McGettigan et al. (2011) [113]	Neural correlates of sublexical structure in phonological WM	N = 17 Experiment 1 N = 15 Experiment 2	N/A	Experiment 1: Covert rehearsal task Experiment 2: Separate passive listening experiment	Digit span task
Powell et al. (2012) [114]	The effect of handedness, language & spatial laterality on verbal comprehension, WM and perceptual organization.	N = 42 (right-handed individuals)	N = 40 (left-handed individuals)	Verbal fluency word generation task	The Wechsler Adult Intelligence Scale
Sahin et al. (2006) [115]	Neural substrates of grammar different from WM, semantics, phonology, or lexical processing. Brain regions that are active in inflectional morphology	N = 18	N/A	Cued covert word generation task	Cued language production (higher WM load) was compared to reading (no load)
Meyer et al. (2012) [116]	Spatiotemporal neuronal dynamics of argument retrieval and reordering processes	N = 14	N/A	Syntactic comprehension and construction task	Task used sentence stimuli that required reordering and retrieving arguments
Bonhage et al. (2014) [117]	Brain mechanisms underlying the sentence superiority effect during encoding and maintenance in WM	N = 18	N/A	Maintenance of sentence structured fragments vs. unstructured word collections	Task manipulated WM load and articulatory suppression during maintenance
Makuuchi & Friederici (2013) [121]	The dynamics of the neural network supporting processing sentences with varying syntactic complexity	N = 22	N/A	Sentence comprehension with manipulation of syntactic complexity	Reading Span task
Newman et al. (2002) [125]	Differences in timing of WM network responses during the presentation of two types (loads) of verbal problems	N = 14	N/A	Written sentences comprehension task	Verbal WM task: two types of verbal problems (early/low load vs. late/high load).
Cooke et al. (2006) [127]	Neural basis for processing different aspects of a sentence depending on WM demands associated with a particular grammatical feature	N = 15	N/A	Sentence-processing task related to its structure-building component	WM resource demands manipulated during sentence processing
Tomasi & Volkow (2020) [128]	The ability to predict reading accuracy and single-word comprehension scores from rest and task fMRI data. The effect of motion in the prediction of language from fMRI data	N = 424	N/A	Semantic comprehension and oral reading recognition tasks	n-back task: 4 different picture categories faces, places, tools, body parts), presented in 8 separate blocks
Mineroff et al. (2018) [134]	The relationship among the language, multiple demand, and default-mode networks.	N = 60	N/A	Language comprehension task (words vs. nonwords)	Spatial working WM task with two different loads