" Specifically, it seems to me that this statement is largely self-evident. After all, it is a basic truth that the more effort someone contributes toward a task, they will realize their goal more efficiently and provide greater productivity. Conversely, a student who does not work to the best of their ability will not be productive and will be unsuccessful. I still do not understand how the authors were able to quantify effort, or how exactly one would validate such a claim. While I can certainly understand a correlation between effort level and a classroom that motivates students to perform at their highest level, quantifying effort level seems as though it would be an impossible task. However, the techniques provided in the chapter are helpful for motivating students in the English language learning classroom. The statement that asking "why" questions is a useful method for enhancing students' curiosity is understandable and intuitive since most native speakers learn the language through asking such questions. Moreover, I would think that asking "what" questions would also be particularly productive in learning a new language as it familiarizes the student with the names for different objects. Conversely, someone who does not ask any questions will not only limit their vocabulary and comprehension of the language but will also fail to develop the requisite inquisitiveness that is necessary in sustaining academic success even after English language fluency is achieved. At any rate, the importance of asking questions is crucial in developing language proficiency.

While I understand the necessity for...

This seems as though it would be impossible; effort level is an arbitrary distinction and quantifying or tracking effort relies on the teacher's subjective interpretation of their students' effort. Just because a teacher feels that their student is not exhibiting high levels of effort does not mean that the student is not trying to the best of their ability, and suggesting that the student is not trying could result in the student becoming hurt or offended, which would negatively affect future performance. Therefore, while it is important to try to ensure that all students are performing at their highest possible level, I feel that teachers should remain sensitive to the possibility that their student may be doing the best they can, even if they have not been successful in realizing any goals that were established.
Chapter 9 also emphasized that rewarding students can be a productive means of motivating them and that the positive recognition can pay dividends in the classroom. This makes sense as people of all ages often perform better when there is some form of extrinsic motivation driving them to perform to the best of their ability. However, I was confused by the chapter's assertion that while rewards can be beneficial, abstract recognition was more effective in improving performance than tangible rewards. While I understand the difference between the two forms of reward, it seems to me that if a student is motivated by an abstract reward (such as a complement or verbal affirmation of their strong effort) this effectively becomes a tangible reward when the student expects it. I feel that the main benefit to more abstract rewards is that it allows for the teacher to personalize the reward (and indeed, the chapter discusses the benefits of personalizing rewards) to a greater degree than with more universal rewards such as a sticker or a piece of candy. To this end, if a student is motivated by a reward -- tangible or otherwise -- this positively affects their effort level and performance.