# An Algorithm for the Detection of Hidden Propaganda in Mixed-Code Text over the Internet +
## 4 Propaganda Detection in Mixed-Code Text
### Writing Styles and Mixed-Code Categorisation  
The way of expressing thoughts in written form can take place differently. Indeed, not only a text is a composition of symbols and characters that are used to build a word in order to convey a message, but it can also be used to depict some phonetic structures or art forms. The basic way of using writing is called _Text on Document (ToD)_, which is characterised by the use of standard alphabetic characters, that is, the symbols belong to a specific language, whose structure is governed by a set of grammar rules, semantics and vocabulary. _ToD_ is supposed to contain an explicit message easy to read and to understand. _Text in Visual Media (TiVM)_, instead, represents the use of the text, in graphical representations, to improve the visual information by imitating sounds or emotions. It might not necessarily follow grammar rules or having any semantic identity. Whereas, a _Text as Art Form (TaAF)_ aims to emphasise the aristry of the writer, by using forms or symbols that are not part of the alphabet, in order to represent a code or a coded message in clear. Mixed-code text belongs to _TaAF_, and according to the conduced research, we classified it into three main types (i.e., _Single row_--_multiple language_, _Single row_--_single language_, and _Multiple rows_) by considering two main parameters, as depicted in Figure 1: (i) the _language_, that is, whether the mixed-code text contains multilanguage factors or writing styles linked to one or more languages and (ii) the _graphical writing style_, that is, whether a standard row-based writing style is followed or multiple rows are used in order to graphically represent the alphabetic characters. Moreover, for each of them further subcategories have been identified, which are described in the following:  
* _Single Script_: the text is written in a particular script, but the basic language might be different. For example, when Hindi is written in Roman script, that means that the script used for Hindi is Devnagri but the usage of Roman script is adopted to write Hindi. * _Multiple Scripts_: the words retain their original forms and scripts but different languages are adopted. The grammar is difficult to grasp; however, the greater number of words used with a particular language generally dominates the grammar rules. * _Third party script_: the text is based on two different languages, but the script utilises a third party script whose grammar fluctuates between the two used languages. * _Alphanumeric_: the mixed code language utilises alphabets and numbers to develop the scripts. It is important that the phonetics of the numbers are in accordance with the reference language. * _Different Alphabetic/Language characters_: the text uses the intended script of the language, but there is also sporadic use of symbols from different languages. The symbols are not part of the language characters but do resemble some of the characters to provide the suitable replacement. * _Special Characters for Alphabets_: the text uses the intended script of the language but it also utilises the special characters in the system to create the alphabet required to sell out the word. The use of special characters may depend on the characters it is required to replace. The characters can be depicted using a single special characters or multiple special characters. This also depends on the code that is being used, i.e., if there is a predetermined set of rules for such replacement, then the special character selection depends on that. * _Multiple size_: the text is written over different height and width. The text may have some characters that vary in size, so as to make the text inconsistent with the standard practise of writing This is generally done to add more effect to the text. * _Inserted symbols_: in this writing form the text is written normally, but it contains symbols inserted among the basic characters to produce a special effect or to decorate a word.