JCPSLP Vol 22 No 1 2020

not always possible to tell which elements of instruction are most crucial. To date, there have been very few studies attempting to isolate the “active ingredients” of these interventions. However, it is possible to draw some conclusions from the existing research. Direct vocabulary instruction When it comes to deep or direct vocabulary instruction, a method known as Robust Vocabulary Instruction (sometimes known as Multiple Context Learning) has been shown to lead to improvements in both vocabulary knowledge and reading comprehension (Beck, McKeown, & Kucan, 2013; Beck et al., 1982; McKeown et al., 1983). It formed part of a successful multi-component study which led to long-term improvements in vocabulary and reading comprehension knowledge (Clarke et al., 2010), and there is evidence to suggest that the effects of Robust Vocabulary Instruction on reading comprehension may be greatest for the children with the weakest reading comprehension skills (Duff, 2019). In a typical Robust Vocabulary Instruction lesson, children see a target word in the context of a written text. They hear it aloud and are asked to repeat it. They are then provided with a child-friendly definition for the word – a definition which uses concepts they already understand (Beck et al., 2013). For example, a child-friendly definition for confide would be “to trust somebody with information you don’t want anyone else to know”. Children are then asked to connect knowledge of the new word to their own experience, for example by being asked “Have you ever confided in someone?”. Then, children complete activities during which they are exposed to the word in a variety of different contexts, and are required to actively use the word. In this way, children develop flexible concepts of word knowledge, which they may be able to apply in their own reading experience. As instructional time is limited, the choice of words to teach is crucial. For school-aged children, sophisticated, literary words with applications in a variety of contexts (such as disappointment or investigate ) are excellent targets for extended, explicit instruction (Beck et al., 2013), as are words which are central to topics children might be learning about (such as habitat or species ; Parsons & Branagan, 2014). The former type of word is often known as a “Tier 2” word (Beck et al., 2013), while the latter is sometimes referred to as a “Goldilocks” word (not too easy, not too difficult; Parsons & Branagan, 2014). For other words, it may be sufficient to simply provide a brief definition before or during reading and instruction. When choosing targets for instruction, we need to consider which words will be the most useful for children at school and in their everyday lives. This involves taking into account a child’s age, the demands of the school’s curriculum, existing oral language abilities, and interests. Ideally, an SLP should work together with a child’s class teacher to develop a set of appropriate words. Parents can also be involved, and can be trained to conduct vocabulary activities with their children at home. It is important to note that if the ultimate aim of vocabulary instruction is improved reading comprehension, then it is crucial for children to know the written forms of words so that they can recognise them in written texts. In a recent systematic review of 23 studies, Colenbrander, Miles and Ricketts (2019) found consistent evidence that teaching a word with its written form (orthography) leads to better learning of its phonological form. This effect is known

children within their caseload who have some degree of difficulty with vocabulary, which in turn may impact reading comprehension. It is crucial that SLPs are equipped to help these children. To that end, this paper reviews the key empirical findings on vocabulary intervention for school- aged children. A systematic review is beyond the scope of this paper – interested readers are referred to meta- analyses by Elleman, Lindo, Morphy and Compton (2009) and Wright and Cervetti (2017). Rather, this paper provides a synthesis of key findings from vocabulary intervention research, with a focus on the ultimate aim of improving reading comprehension. What has research taught us about vocabulary instruction? Broadly, there are two ways to approach vocabulary instruction. The first method is sometimes referred to as a “deep” or “rich” approach (e.g., Beck, Perfetti, & McKeown, 1982; McKeown, Beck, Omanson, & Perfetti, 1983). Under this approach, children receive direct instruction in word meanings, with repeated exposure to the same words, and extended practice using and applying the word meanings in context. The aim of this approach is to provide children with rich concepts of word knowledge that can be used flexibly in a variety of situations. The second method is sometimes referred to as a “broad” or “wide” approach (e.g. Bowers, Kirby, & Deacon, 2010; Nagy & Herman, 1984). Under this approach, children learn strategies for working out word meanings in context, such as using morphological knowledge to work out meanings of complex words, or searching for words that might provide clues to the meanings of other words. The reasoning behind this approach is that it is impossible to teach children every word they need to know, and in typical development, most vocabulary knowledge is picked up incidentally via independent reading or experiences with spoken language (Nagy & Herman, 1984). “Broad” methods aim to equip children with strategies to better learn words from their own experience. Clearly, the fact that a child has poor vocabulary knowledge for their age is an indication that they struggle to pick up new vocabulary from their written or spoken language experiences. In this situation, a broad approach alone is unlikely to be sufficient, and deep, direct vocabulary instruction is necessary. However, it is also true that the amount of direct instruction required to help such children “catch up” would be extensive. For example, Biemiller (2003) estimated that children with vocabulary difficulties would need to learn approximately four new root words per day over five or six years to catch up to their typically developing peers. Therefore, it makes sense to also teach children strategies to help them learn new word meanings from their language experience. Existing research suggests that the combination of both deep (direct) and broad (strategy-based) methods is likely to be more effective than exclusive use of either approach alone (Wright & Cervetti, 2017). Furthermore, the studies that have been the most successful in improving children’s vocabulary knowledge and their reading comprehension have been multi-component ones combining direct vocabulary instruction with strategy instruction and other types of language-focused instruction, such as figurative language or text structure instruction (Clarke, Snowling, Truelove, & Hulme, 2010; Language, Reading Research Consortium (LARRC), Jiang, & Logan, 2019; see Table 1). The difficulty with multi-component studies is that it is

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JCPSLP Volume 22, Number 1 2020

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