Chapter 6. Understanding Text

The previous chapter covered the speech APIs. Throughout this chapter, we will look closer at more language APIs. We will learn how to use spellcheck features. We will then discover how to detect languages, key phrases, and sentiment in text. Finally, we will look at the translator text API to see how we can detect languages and translate text.

By the end of this chapter, we will have covered the following topics:

• Checking spelling and recognizing slang and informal language, common names, homonyms, and brands

• Detecting language, key phrases, and sentiment in text

• Translating text on the fly

Setting up a common core

Before we get into the details, we want to set ourselves up for success. At the time of writing, none of the language APIs that we will be covering have NuGet client packages. As such, we will need to call directly to the REST endpoints. Because of this, we will do some work beforehand to make sure that we get away with writing less code.

New project

We will not be adding the APIs to our smart-house application. Using the following steps, create a new project using the MVVM template that we created in Chapter 1, Getting Started with Microsoft Cognitive Services:

1. Go into the NuGet package manager and install Newtonsoft.Json. This will help us deserialize API responses and serialize request bodies.

2. Right-click on References.

3. In the Assemblies tab, select System.Web and System.Runtime.Serialization.

4. Click OK.

5. In the MainView.xaml file, add a TabControl element. All our additional views will be added as TabItems in the MainView.

Web requests

All the APIs follow the same pattern...

Correcting spelling errors

The Bing Spell Check API leverages the power of machine learning and statistical machine translation to train and evolve a highly contextual algorithm for spellchecking. Doing so allows us to utilize this to perform spellchecking using context.

A typical spellchecker will follow dictionary-based rule sets. As you can imagine, this will need continuous updates and expansions.

Using the Bing Spell Check API, we can recognize and correct slang and informal language. It can recognize common naming errors and correct word-breaking issues. It can detect and correct words that sound the same, but differ in meaning and spelling (homophones). It can also detect and correct brands and popular expressions.

Create a new View in the View folder; call the file SpellCheckView.xaml. Add a TextBox element for the input query. We will also need two TextBox elements for the pre- and post-context. Add a TextBox element to show the result and a Button element to execute the spellcheck...

Extracting information through textual analysis

Using the text analytics API, we are able to analyze text. We will cover language detection, key-phrase analysis, and sentiment analysis. In addition, a new feature is the ability to detect topics. This does, however, require a lot of sample text, and as such, we will not go into detail on this last feature.

For all our text-analysis tasks, we will be using a new View. Add a new View into the View folder called TextAnalysisView.xaml. This should contain a TextBox element for the input query. It should also have a TextBox element for the result. We will need three Button elements, one for each detection analysis that we will perform.

We will also need a new ViewModel, so add TextAnalysisViewModel.cs to the ViewModel folder. In this, we need two string properties, one for each TextBox. Also add three ICommand properties, one for each of our buttons.

If you have not already done so, register for an API key at https://portal.azure.com.

Add a private...

Translating text on the fly

Using the translator text API, you can easily add translations to your application. The API allows you to automatically detect the language. This can be used to serve localized content, or to quickly translate content. It also allows us to look up alternative translations that can be used to translate words into different contexts.

In addition, the translator text API can be used to build customized translation systems. This means that you can improve the existing models. This can be done by adding existing human translations related to expressions and vocabulary in your industry.

The translator text API is available as a REST API. We will cover the four endpoints that you can reach. To use the API, the following root URL should be used:

https://api.cognitive.microsofttranslator.com

Sign up for an API key at Microsoft Azure Portal.

Translating text

To translate text from one language to another, you should call the following URL path:

/translate

The following parameters...

Summary

In this chapter, we have focused on the language APIs. We started by creating the parts that are needed to execute the API calls to the different services. Following this, we looked at the Bing Spell Check API. We moved on to more analytical APIs, where we learned how to detect languages, key phrases, and sentiment. Finally, we looked into how we can use the translator text API.

The next chapter will take us from language APIs to knowledge APIs. In the following chapter, we will learn how to recognize and identify entities based on context. In addition, we will learn how to use the recommendations API.